Yesterday I learned from a Mainland website that a "history professor" of Taiwan said in an ERA news'(年代新聞) talk show that Song Dynasty was divided into a North and a South, and they'd never been unified with each other; therefore, the separation as a political status is pretty normal throughout China's history.  What? I just couldn't believe my eyes!  (Scarcely I watched that kind of talk shows which had been fraught with inanities and follies; I'd rather call them political comedies.)

It is such a common sense that Song Dynasty became de jure extinct when Jing Dynasty replaced it in 1127; however, its sovereignty continued to exist over the southern part of China for another 150 years until it was annihilated by Mongolia in 1279.  For the dynasty itself, it had been an entirely Song, but for the convenience of historical study, people referred to the former one as North Song, and to the latter one as South Song.  They had never been "independent" to each other; therefore, there was no "unification" problem ever existed.

I know that "history professor"; he is a graduate of history from NTU alright.  But I am not sure if he is now a "professor" or not.  Oh my goodness!