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The rise and the rainfall of the Roman empire

A link between drought and the fate of ancient emperors bodes ill for modern times

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Aug 1st 2018

by THE DATA TEAM

DURING the past two months, the world has been stifled by exceptional temperatures. Deadly wildfires have ripped through parts of the United States and Greece; Japan has declared its heatwave a natural disaster; drought in Britain has led to hosepipe bans and caused farmers to slaughter their cattle for lack of feedstock. As the planet warms, global heatwaves and associated droughts will become increasingly common. History offers numerous cautionary tales about the effects that these weather-related shocks can have on society and politics. 

One such lesson is how drought affected the stability of the Roman empire 1,500 years ago. In a new paper published in Economics Letters, Cornelius Christian of Brock University and Liam Elbourne of St Francis Xavier University identify a strong association between rainfall patterns and the duration in power of Roman emperors. The academics hypothesise that lower precipitation reduced crop yields, leading to food shortages and eventually starvation for soldiers stationed at the empire’s frontiers. As a result, troops were more likely to stage mutinies and assassinate their emperor. 

The academics combine data on assassinations—some 25 emperors were assassinated, roughly one-fifth of the total—with precipitation data collected from rainfall-sensitive oak-tree rings across the Roman frontier in France and eastern Germany. They find that a one-standard-deviation decline in annual rainfall (a 20% reduction from the average) was associated with an increase of 0.11 standard deviations in the probability that an emperor would be assassinated the following year. The Gordian dynasty from 235 AD to 285 AD was particularly tumultuous: 14 of the 26 emperors who ruled were assassinated during this period. Of course hungry troops were not the only cause of the demise of emperors. This period was also marked by plague, invasions and economic depression. 

It might be easy to dismiss the lessons from 1,500 years ago. Ancient Rome had little ability to store grain for long periods or irrigate crops. Yet, to this day, dictators rely on an obedient army to retain power. And more broadly, it has been long established that adverse weather causes economic shocks that lead to unrest, and even to civil war. For example, droughts are widely cited as a cause of civil war in Sudan, and of the rise of Boko Haram in Nigeria. In 1,500 years little has changed: extreme weather events, caused by climate change or not, tend to increase political instability.

以下是原文引用的論文目錄頁：

https://www.sciencedirect.com/science/article/pii/S0165176518302532

筆者花了兩個單篇幅5000字元限制，以回文方式貼了兩篇如下：

The rise and the rainfall of the Roman empire

Aug 11th, 15:21

This year Antarctic’s snow alters with intermittent reddened. Searched by Japanese Nikoniko Non and published by “Nature”, the cause of façade is derived of a certain algae which belongs to erythrophore. The microorganism, fitting in the warmer environment, loves UV while worst of all making the cells warmer, with a resultant goes at higher temperature of the swathe.

In search of the classics and writings on my bookshelf, like Shiono Nanami’s “Res Gestae Populi Roman”, Feng Tzou-ming’s “Occident Complete History” and Edward Gibbon’s “The History of the Decline and Fall of Roman Empire”, the coup d’état has poor direct relation with the rainfall, amount of which influences the crop and sanitary condition. Yet the RE agricultural (AG) regression during a somber century (CE) in RE’s history, is said to reflect the coeval PO stability obviously.

Wheat was the largest harvest everywhere in RE. In fact, the Rome imported wheat from Egypt and North Africa (NA), wine from Gaul (G, now France), and oil from Iberian Peninsula (IP, now Spain) and NA for the major crop. With the imperial expansion since the rule of Julius Caesar (JC), the Romans began to cultivate more land when they brought Mediterranean (MED) plants and more sophisticated farming methods farther north into G, the Rhine valley, and the Balkan Peninsula. Moreover, the Romans cultivated cash crop like Vineyards throughout G, and olive groves planted in NA that generated a diversity of Roman cuisine. The Romans learned new techniques for farming in wet climates that allowed them to open new lands for agriculture in northern G and Britain, where increasing demands for timber transformed native forests into AG estates.

The concern that less rainfall is associated to the more assassinations (ASS) infers why the Roman Empire (RE), founded by Emperor (EM) Augustus (AUG) Octavian and ever having 70-90m population, was confined by the occult 12 bold eagles that helped Romulus construct Rome, the largest 1.2m population, even if the artificially compilation of Roman Law (RL), referred to as the inception of today’s civic law “Les duodecim tabularum”, guarded by the “Senatus Populus que Romanus” involving colossal bureaucracy (BU) headed by “Consilium”, “Clientes”, negotium-otium regularity, in line to trading prevalence based on the agribusiness, transportation and monetary policy, and splendid legionary assemblage sustained over thousand years’ imperial taxation and prosperity. RE nation prefer the debating, universal multifarious taste of subject in a mix of polytheism.

Historians often focus on political (PO) leaders, but it is local grievances about high taxes, crime, or the price of bread that most often provoke people to revolt against a government. The Romans who always strutted around like they dominated the universe relied on civil laws to address a variety of any secular issues. RL in the republic was often based on custom, and in the imperial on inscription. Since AUG, the EM became the final source of law. Yet from modern perspective of democracy, the lack of systematic constitutionalism is the clanger of the state’s preservation.

The miserable period I amplify here to take example began from the extravagance, violence and license of EM Commodus (COM), EM Marcus Aurelius’ (AU, the last “5 Good EM” and Stoic philosopher, 121-180) son, and ceased in the abolishment of PG by Constantine the Great’s (CON) reign. Frontier troubles increased the cost of the army, and the BU continued its inevitable growth. The empire was no longer expanding, and rising costs far outstripped the limited economic growth possible in a preindustrial economy. About 160 when “Pax Romana” saw the Rome’s civilian jocund, the sneak economic decline nevertheless began to imperil the RE safety that the later CEs’ EMs had worked so hard to maintain. In the 2000 movie “Gladiator”, Joaquin Phoenix played protagonist of COM that introduced the RE destiny at crossroads. The portentous cataclysm and the Germanic tribe’s (GT) invasion emerged after AU’s accession, but the RE interior unity hadn’t ruptured until the death of COM who assumed his own title of Hercules Romanus ceded the land AU had conquered to GT.

Since 190, pandemic (PA) spread making thousands of deaths each day for 2 years in Rome. In that June Rome was afflicted by a food shortage, when the Chamberlain Cleander (CL), in charge of the grain supply, contrived to make worse than actually it. Even if CL was executed by COM, the Senatus ASSed COM and his corpse was thrown into Tiber in 192. The final ASS of the somber CE referred to EM Maxentius (MAX) drowned by the soldiers expelled by CON in Tiber and then MAX’s father EM Maximilian suicided in 313 while failing to battle against EM Licinius later executed by COM. It indicated the CEs-long measures of food distribution crack and the cabal turned to easily evoke convulsion to exaggerate the militia’s strata, that led to the larger social inequality. (to be continued)

The rise and the rainfall of the Roman empire

Aug 11th, 15:24

The heinous decadence of power struggle, avarice, and the decay of national confidence exposed to twisted humanity to RE national security, largely owing to the rampant Praetorian Guard’s (PG) volatility. PG gradually began to tighten the grip in an unscrupulous manner, deposing and elevating EMs at their pleasure. In 193, after the ASS of Pertinax, the 1st slave-born EM, they sold the throne to the RE richest Julianus. Worst of all, a PG prefect Marcrinus usurped the authority of EM Caracalla (CA), EM Lucius Septimius Severus’s (SEP) immoral son. SEP’s 5 successors, including both his sons Geta and CA, were all murdered. Since COM’s death in 211, until the reign of EM Diocletion (DI, called “Dominus et deus”) who first separated entire territory for the efficient governance, 16 out of 24 (Senatus granted) RE EM were murdered. That is, the imperial crown’s owner especially PG proclaim mostly meets these EMs doom. In fact, the period after the ASS of the SEP’s last successor EM Severus Alexander is called military anarchy (MA, or Crisis of the 3rd CE) mixed by the EM backed by PG, Senatus, people, legionary and by the EM’s own among over 40 either anonymous or notorious array.

Since the MA’s early days, the Greater Yuezhi (Scythians), the Parthian EM (BC 250-AD 224) and the later Sassanid EM (224-651) in the east, Scots and Celts in the Britain, and the Vandals and Goths in the north dared to challenge the CEs-long Occident order of Armenian-allied RE dominion after the EM Philip celebrated the Rome’s founding millennium in 248 the eroded the RE sovereignty with the capriciously natural disaster.

GT’s emigration, apparently since 0.3m “pirates” emerged first in the MED during 252-253, was pertinent to the dearth of AG know-how, although the GT aboriginal region fits the farming. TE’s chart drops a hint of the reference that could compare to the GT’s eagerness of the RE fecund AG-oriented economy in shift to fortune in the meantime. The arid landscape’s expansion made farmers feel more fear while the PA entangled with implacable battle and natural disaster. Along the border the inhabitants lost their farms sapped by GT’s sedition and then joined in the “Curia Regis” at the frontier. Either GT was allowed to own or successfully grab the farm near border, GT largely used it to extort money more rather than harvest the crop. Thus, the domestic AG productivity, except for RE territory in NA, downgraded.

Since then, the poverty that resulted from the decline in trade discouraged the local elite from holding offices. Civil war and the collapse of central authority affected every aspect of Roman life. While moving armies commandeered supplies from farms and cities, imperial tax collectors made increasingly harsh demands for funds to support the armies and BU. So many peasants (PEA) fled the farming land to work for large landholders or turned to robbery. It affected the stability of crop’s trades, especially the cash crop’s aspect, and made the supply chain incapacitate.

The RE military began to take responsibilities for the productivity’s regain that nevertheless led to the lower morale. For instance, RE militia became so extremely indolently exhausted after expatriating 0.4m in G (today’s France), conquering Goths and Isoria that ever ASSed EM Probus who ordered them to help farming at his birth place. Maybe the fewer rainfall help the nuisance spring up to maturity enough to shackle the RE’s fortunate.

Moreover, in the late 3rd CE, the military spending while training recruits from Rome Civics burdens RE finance with the silver-standard system broken, although CA started to render the provincial inhabitants (heavier 10% tax) outside Rome equivalent of civil right (Rome Civics nearly free) that helped the authority implement the stout armed security at the expense of sufficient taxes. For instance, the MA of past regimes had caused economic collapse as those rival EMs produced worthless coinage to pay their troops. By 270 the silver content of the coinage was only 1%. This devaluation of the currency soon had a terrible effect on RE until DI’s reform on RE finance.

The DI who began RE’s age of absolute monarchy took the stricter measures. The rural people that couldn’t afford to pay higher tax thronged the cities abandoning the farm. Before then, the “ager publicus” JC promulgated kept the sustenance of PEA and AG slaves who ensured the RE solid fundament. Satirically, they no longer escaped from the foreign foes due to DI’s severe military tactics, disciplinary and recuperative morality but they alternatively joined up for tax-evasion array. The economic regiment “Edict on Prices”, inclined to authoritarian way, indeed transiently kept a pillar of CON’s halcyon days and later 1.5 CE’s RE arduous maintenance. And the serious social disparity was why - even if the rainfall’s amount per year returned to the level of EM lifespan’s average or above - the RE finally terminated at the hands of a GT King Odoacer.

今天來聊這數千年上承古代東方文明及希臘文化，下接兩支中古黑森林的世紀及偏安巴爾幹小亞細亞海灣拜占庭，的羅馬帝國是如何崩盤的。主題既然是降雨量和羅馬帝國國勢的關係，以政治謀殺數據來作比較，筆者拿在日經中文網看到的一篇氣候變遷的證據感慨一下作第一段。這種探究之前不少相關報導及研究，主要著眼現今法國、西班牙及義大利一帶的年輪和降雨，比對歷史資料所知，不過是民族大遷徙和氣候的變化，相類似於，筆者以前小時候看牛頓雜誌所聽聞日本學者研究中國五胡亂華和氣候變冷的一個問題。筆者有興趣翻了三套書花了要一個禮拜寫，三民書局所出版的塩野七生的「羅馬人的故事」繁體中文版（鄭維欣編譯），裡面XI「結局的開始」、XII「迷途帝國」、XIII「最後一搏」，和「關於羅馬人的二十個問題」，燕京出版的馮作民先生的西洋全史第四本「羅馬興亡史」及簡體中文版的Edward Gibbon’s “The History of the Decline and Fall of Roman Empire”的第1卷pdf掃描檔，最後還參考了「BuzzOrange報橘」網頁有一針見血的分析根本是公民權問題衰頹的論點。筆者想到以前有個愛打線上電動的大學朋友張惟翔，很喜歡這套塩野七生的「羅馬人的故事」，筆者是從2005年底開始蒐集的。

從Octavian屋大維(Gaius Julius Caesar, 生卒日BC 630923- AD 140819)當Augustus皇帝起，筆者截取微軟大百科全書Encarta 2009的「Roman Empire」項目來說（不過羅馬帝國史曾經有過「三十僭主」問題，筆者在回文中的數數被政治謀殺的皇帝數目，以塩野七生及馮作民西洋全史的第四本羅馬興亡史的算法），而大英百科全書Britannica 2013很奇怪的是，沒什麼說明羅馬帝國是什麼，除了以人物為主來寫的「斷代史」，亦即連續性「通史」來寫並沒有：

Julio-Claudian Emperors：27 bc-14 ad Augustus 14-37 Tiberius I 37-41 Caligula (Gaius Caesar) 41-54 Claudius I 54-68 Nero

Civil Wars：68-69 Galba 69 Otho 69 Vitellius

Flavian Emperors：69-79 Vespasian 79-81 Titus 81-96 Domitian 96-98 Nerva 98-117 Trajan 117-38 Hadrian

Antonine Emperors：138-61 ¹ Antoninus Pius 161-69 ¹ Lucius Verus

Despotic Emperors：161-80 Marcus Aurelius 180-92 Commodus ² 193 Pertinax 193 Didius Julianus

The Severi： 193-211 Septimus Severus 193-97 Clodius Albinus 193-94 Pescennius Niger 211-217 Caracalla 211-12 Geta 217-18 Macrinus 218 Diadumenianus 218-22 Heliogabalus 222-35 Severus Alexander

The Soldier Emperors： 235-38 Maximinus 238 Gordian I 238 Gordian II 238 Balbinus 238 Pupienus 238-44 Gordian III 244-49 Philip I, the Arab 249-51 Trajan Decius 251-53 Trebonianus Gallus 251-53 Volusianus 253-60 Valerian 253-68 Gallienus 268-70 Claudius II 270 Quintillus 270-75 Aurelian 275-76 Tacitus 276 Florianus 276-82 Probus 282-83 Carus 283-85 Carinus 283-84 Numerianus 284-305 Diocletian ³ 286-305 Maximianus 293-306 Constantius I 293-311 Galerius 306-337 Constantine I

1) Divided voluntarily between two brothers.

2) Between 180 and 284 there was a succession of emperors placed on the throne by their respective armies or factions. Therefore, dates of emperors reigns in this period often overlap.

3) The end of Diocletians reign marked the split of the Roman empire. Whereas Diocletian retained supreme power, Maximianus ruled Italy and Africa, Constantius I ruled Gaul and Spain, and Galerius ruled Thrace.

筆者以這張帝系表輔助來說，放大從五賢帝的最後一位號稱哲學家皇帝的奧理略(Marcus Aurelius, 在位161-180)及其親生長子高摩達(Commodus, 在位180-192)在位時的作為及天災不斷，到名傳古今的君士坦丁大帝(Constantius I, 在位306-337)奠都於今天伊斯坦堡，總體上開始了羅馬帝國一去不復返的衰頹，從這段政治謀殺最密集，也是帝國國祚雨量最低的百年左右。曾著「冥想錄」的奧理略還能夠維持羅馬帝國的體面，應付在位時比前幾任多的天災，不過的確是不祥之兆，隱隱約約的衰頹包括行政官僚的擴大及未被認為是問題的社會階層制度。在2000年上映的神鬼戰士電影，這對父子就是雙主角，繪聲繪影地說奧理略就是被他的兒子用計殺死的。

史家公認高摩達是由盛轉衰的羅馬皇帝，高摩達愛好方術，身材魁梧臂力過人，儘管他的人格極為卑下，日夜沉溺於酒色，但羅馬人民在其即位之初感念其父的餘德，又其常以希臘古英雄海克力斯自比，在即位大典上把自己頭髮沾滿金粉，滑稽模樣不亞於尼祿帝。對內鴨霸人民，對外把其父戰勝日耳曼蠻族多瑙河五英里之外的土地全部還回給馬克曼奈族。元老院(Senatus)在五賢帝時代後居然反民主地開始組織謀殺黨，而禁衛隊這是也是在五賢帝時代後開始成為權力核心，這時正受高摩達寵愛遙控政局，兩派傾軋不已。

這表面上和降雨主題無關，不過筆者試圖找尋這關係時，一開始無直接關係證據。降雨和農產量有關，又羅馬帝國處在「pre-industry」前工業社會，以農業經濟為主的貿易及商業社會所組成，又羅馬帝國長期貨幣通行，帝國中央有一定的經濟政策維持，在君士坦丁大帝之前是銀本位，之後是金本位。而就供應鏈而言，農業的收成產量和農穫品質，包括糧食及經濟作物會影響各行省城市及首都羅馬的經濟狀態，當然也影響民心士氣。約西元190年開始，羅馬發生嚴重的瘟疫，其後又有糧荒，是禁衛軍的統領科林德進行囤積之故，因此本來實施的公民的配給制受影響，饑民抗議遭禁衛軍屠殺，駐守的城防軍見義勇為和禁衛軍起衝突。雖然高摩達把科氏趕到宮門外讓他被亂民打死，首級示眾，但是謀殺黨買通高摩達的妃子下毒絞殺，被元老院公告是羅馬公敵，把他的屍體丟到台伯河餵魚。實在是不應該拿公發物及天災當幌子作貪汙及玩笑來愚弄百姓。不過回顧到這裡還沒有說和降雨量或農作物有直接關係。

一般認為是人性貪婪，風紀敗壞，法治不彰而起。筆者繼續一個一個比對。元老院和軍隊的擁立加劇，第一個奴隸出身的皇帝柏提那克斯(Pertinax)整頓禁衛軍不成被弒，這帝位還會被當商品被禁衛軍販賣給鳩力那斯(Didius Julienus)。而塞弗拉斯(Septimus Severus, 在位193-211)結束了阿爾比納斯(Clodius Albinus)和奈哥(Pescennius Nige)創立塞弗拉斯王朝，其後五個繼承者，包括兩個兒子、孫輩和皇后的後代，就算有所作為並沒有獲得善終，這五位關係在馮氏西洋全史敘述上稍微含糊了些。這時軍人已經跋扈成性，任意廢立時有所聞。

筆者遂把角度調往之後第三世紀中葉，一個阿拉伯裔將領出身的菲力普帝(Philip, 在位244-249)在舉行建國一千年大祭，在羅馬城走馬看花的那幾個月後，羅馬帝國和蠻族的消長逐漸傾斜於蠻族，帝國軍隊幾乎年年窮於應付日耳曼民族，不是只有從凱薩時期就已經很煩羅馬人的高盧人(Gaul)、帕禔亞人(安息帝國，the Parthian Empire BC 250-AD 224)，進入第三世紀時的來自帝國得喜亞州，多瑙河口的大月氏(the Greater Yuezhi ，又稱Scythians) 及繼帕禔亞帝國興起在伊朗高原的薩珊王朝波斯帝國(Sassanid dynasty, Persian Empire 224-651)，還要顧不列巔群島的蘇格蘭人(Scots)和賽爾特民族(Celts, 包括蓋爾人)，以及只會越來越兇狠的汪德爾人(Vandals)與最後滅亡西羅馬帝國的哥德人(Goths)的加入。

其後，除了戴克里先(Diocletian, 在位284-305)和君士坦丁大帝的均勢，中間過了東羅馬帝國法倫斯帝(Valens, 在位364-78)和西羅馬帝國法倫廷尼安帝(Valentinian, 364-75)兄弟檔，到了最後一個分東西的狄奧多西(Theodosius, 在位346-95)皇帝，兩個黃口小兒阿卡德(Flavius Arcadius Augustus, 在位395-408)當東羅馬帝國皇帝，韓諾留(Flavius Honorius Augustus, 在位393-423)是西羅馬帝國皇帝，抵擋不住越來越多的蠻族如法蘭克及布根弟族入侵，甚至到匈奴族的阿提拉大帝(451年入侵高盧)，西羅馬帝國風中殘燭至日耳曼酋長鄂多阿塞(Odoacer, 生卒年433-93)在476年9月篡了羅馬拉斯帝(Flavius Romulus Augustus, 在位475-476)。

筆者的印象中，若說有使羅馬帝國的非政治因素導致滅亡，是鉛的金屬中毒使羅馬臣民變笨。基本上，天氣的變冷而雨量減少，所以相對於當時羅馬帝國的北方的蠻族，在萊茵河、多瑙河以北、黑森林地區及今波蘭、烏克蘭及南俄一帶的諸部落，雖然故地也很適合農耕，但是這些祖居地為斯堪地那維亞的民族部落仍然習慣幾千年的游牧生活，筆者歸納起來是懶惰到不想下田，而遺傳上高大粗壯，習慣騎馬打獵和帳蓬生活，和羅馬男子平均170公分相比有明顯優勢，於是拿來攻擊富庶的羅馬帝國屬地行省，這是北邊的情形。東邊則是從凱薩大帝開始的和帕禔亞、波斯的你來我往。

筆者也在比對羅馬帝國的農業產物分佈，如糧食作物穀倉在北非，在東方行省如今敘利亞等地因為有世襲貴族協助作生意成為稍微多的稅收來源，而羅馬帝國在初期有鼓勵經濟作物的擴張，如葡萄子、橄欖樹枝、酒和油在高盧、伊比利半島和得喜亞州(今羅馬尼亞)各地等。如果單看這些，還是沒有找到直接關係，筆者發現帝政初期和中期也是有雨量變化，或是天災人禍慘重情事，但是無礙國運。有一個論點是喀拉凱拉帝(Caracalla, 在位211-17)公民權的發放給行省居民，拿了羅馬公民的好處是幾乎免稅，還可以分配到基本口糧，又可以取得募兵制士兵的資格，以此途徑獲得參政權，而一開始實施的時候，一般民眾對於羅馬帝國軍隊的印象是無往不利，雖打仗比帝政初期多了些，但是戰利品和奴隸每每滿載而歸，真可謂有呷，又有抓仔，又可以僋到，算起來各省屬民效忠度最高就是這個喀拉凱拉帝當政時期啦，羅馬官吏每幾年都會評估每個公民要繳多少時，那就是變相趕人去當兵，說自己有軍籍在行伍就好啦。於是開始有個風氣就是不想下田了，這和北邊日耳曼民族相似，之後數百年歐洲史就是民族間不想下田的互鬥。更嚴重的是，為了發軍費所使用的銀幣含銅95%以上，助長民眾虛偽風氣，首都羅馬城宵小橫行治安敗壞。

看到這裡，雨量是其次，不過有研究指出雨量有時稍嚴重而已，因為會有災區產生，但是部隊認為下田為低落行業，硬逼要下田搞死皇帝的名例：曾經有過整團士兵在一氣之下，把普羅巴斯帝(Probus, 在位276-282)弄死在其故鄉灌溉工程鐵塔現場的慘事。據塩野七生的「羅馬人的故事」套書中，在三世紀後半葉每次的災區重建變得遲頓，好處是這樣災民就可獲免稅待遇，而官員會故意不協助重建獲民眾支持，又收了一堆士兵，然後政府要瘋也似的付軍費放款，民粹橫行。為軍費而被近臣刺殺的還有馬克西明帝(Maximin, 在位235-238，即結束塞弗拉斯王朝的皇帝，出身色雷斯牧羊童)，因為愛屠殺富人沒收財產(不少羅馬皇帝喜歡這麼作)，各地不堪其暴政，更會對自己人殘忍下令，在阿揆雷阿城(Aquileia)被叛兵殺死; 奧利連帝(Aurelian, 在位270-275，在回文中筆者沒有寫這兩位皇帝)，因為要急著籌措軍費，又以嚴刑峻法監察甚嚴，嚴到讓群臣組成謀殺黨把皇帝搞死在波斯遠征軍中。雨量變稍微少，或是境內天氣狀況不穩定個幾次，就會讓這種荒唐的事情一筆一筆使羅馬帝國的榮耀消逝，在這戰亂頻仍半世紀來，人性的貪婪腐敗在羅馬帝國境內各處暴露無疑。佃農和農奴不下田，跑去城市發展，或是透過作兵，除了逃稅也可以順著提升階級追逐名利，這就說得過去何謂雨量影響政局穩定了。

筆者最後一段是從戴克里先皇帝，想出又是搞東方君主專制朝儀並搞嚴密監察、改革幣制及稅制但是劣幣驅逐良幣、一手極權削弱元老院為諮議局來作破壞性思考實踐，又是人類政治史上第一個作司法、立法、行政三權分立機構的政府-雖然都聽命於皇帝，並繼續嚴厲迫害基督教徒，即基督教史的「殉教時代」。退隱於今克羅埃西亞境內而過了九年種鮮綠大白菜的戴克里先，是近百年三十位軍人皇帝裡面，唯一功德圓滿而最後又得善終的一位。這是一種試圖脫胎換骨，但更像是勉強維持住帝國的頹勢，而立的急就章告示而已，也成為羅馬帝國被滅亡的遠因，戴克里先沒有解決實際上的社會階級化分，稅金的重新計算對於農民太苛，逼得更多人跑去城市，而因農產減少，手工藝和商人的收入變得不穩定，長年爭戰。人民在頒布「米蘭敕令」及召開「尼西亞會議」的君士坦丁大帝的德政下，帝國四區高盧、義大利、伊利利亞和東方區共轄13州116郡，遷都君士坦丁堡使國祚延了千年之久，解散擅權的禁衛軍改由野戰軍和守備軍駐守。可惜後人不知羞恥，一味貪權不事生產，後來僵硬的法制比如十五年查一次收入狀況定稅金，但和實務上蠻族年年問候羅馬皇帝不符，帝政最後幾年，沒資產還要繳稅使原來會效忠的公民就這麼不負責地鳥獸散了。

當然帝政初期和後期也有政治暗殺的情事。筆者刻意選擇回憶這段和禁衛軍的亂政問題相關的時期，而且就史家記載，連年災情不斷、與蠻族爭戰及內戰的紀錄的史料正好可以成為例證。羅馬的官僚組織在這時期還算完備，戰戰兢兢的悶頭作事。日耳曼族裔在履次以合約或非法的成為羅馬士兵、公民和官吏者越來越多，於是滅亡了西羅馬帝國。這些故事聽起來和現在什麼政治社會沒什麼關，不過若提起人性、法治和大小事件前因後果的串接，不仿聽一下學者們曾經認為成也蕭何敗也蕭何的羅馬法，一開始是慣例法，後來判例居然搞得僵化而條文化後，容易因無所適從滅亡。也就是說，缺乏憲政主義的羅馬帝國的前工業社會，沒有任何限政的觀念和政治菁英共識，徒留西塞羅(Marcus Tullius Cicero, BC 1060103-BC 431207)的自由主義學說及與屋大維貌合神離的古羅馬憲制三權分立的想法迴蕩在地中海。又君士坦丁大帝的後人在施行政策上想頭不想尾，除了窮於應付的沉重財政負擔，搞成一窩子士兵又有蠻族血統，又有屬省人民，也有羅馬的口令的雜牌部隊，越和所謂蠻族對陣也算是內戰，除了缺乏頭腦，羅馬士兵為了財物而戰的心態太重，尤其是君士坦丁大帝死後的西羅馬帝國。

筆者小時候看過西洋全史後，不會特別排除卜筮之說，除了不能證明說法為明顯有誤之外，有時真的就這麼被說中了，人定勝天的極限可見一斑。再回想起一個國祚的巧合在西洋全史第五本「中古歐洲上冊-黑暗時代及其以後」的第244頁：早在五百年前的西塞羅時代(凱薩被刺死後由西塞羅和安東尼, Marcus Antonius, BC 830114- BC 300801, 擔任共同執政)，羅馬卜者之間就流行一種預言：「羅馬開國始祖，以十二隻禿鷹而戰勝其弟雷摩斯，故羅馬帝國之壽命將為十二世紀。」但是那個時代正係羅馬國勢鼎盛之時，任何一個羅馬人也沒重視這項預言。可是現在西羅馬帝國內憂外患交加，整個帝國似乎已經瀕滅亡的邊緣。當時羅馬人算一算，從西元前七五三的羅馬開國，到現在已經滿了十二個世紀，於是他們才開始重視這項預言，莫不為祖宗所建千年帝國羅馬的即將滅亡而驚恐與憂傷。果然不錯，這項預言竟一語成讖，大羅馬帝國的根幹，真就在羅馬建國後的1229年滅亡，比五百年前預言的只多29年而已。這究竟是「天意」呢還是「巧合」呢？人間之事往往就是這樣玄虛奇妙。

另參考網路一篇以喀拉凱拉皇帝Caracalla公民權的開放以充實兵源但稅金短少的著力點來看：歷史解密》古羅馬帝國是怎麼毀滅的？ 一切的源頭居然是開放公民權害的

https://buzzorange.com/2016/04/19/rome-collapse/