to degenerate; impoverished; to fall (into poverty); to be reduced (to begging)

to fall into enemy hands; to be occupied; to degenerate; to submerge

to sink down to; to be reduced to (sth inferior)

(of a country) to perish; to be annexed; subjugation (to a foreign power)

to be lost; to be ruined; to perish; to wither away

to sink into (vice, depravity etc); to pass into oblivion; downfall; passing