是離愁

李煜 or 李後主 is the last monarch of 南唐. When his father 李璟 was in position, 李璟 already conceded to the emperor of 後周.

A life of debauchery, you might call that he lived... deliberate of not, your own judgement call...

What got him killed were his verses (excuses, perhaps)... "故國不堪回首月明中", "恰似一江春水向東流"。

是離愁 別是一般滋味在心頭

What a different flavor--- eternally to depart-- soon-- such he had already known.