I never quite understood the German interest in Eagles, the Romans used them, then the Imperial French both of whom the Germans are famous for beating so why steal and glorify the badge of the loser? Too much classical education i guess and everybody believing that Rome was the only true lasting civilisation?
The obvious one with Christianity is Christmas, as near as anybody can tell Jesus was born sometime in the middle of the year, the date got shifted to take over several notable pagan festivals.
The one that always interests me is constant appropriation of Greek buildings, particularly for civic buildings to do with public functions. If its supposed to be democratic then slap a few Dorics out the front and some scantily clad babe with an owl or a cornucopia on the roof and bingo, instant symbol of public democracy. Admittedly we just pinch the buildings, the yanks go all out and call the whole town Athens or Sparta to really set the tone but how many times have you seen Greek pillars on the front of an official building?