The Wars of the Roses was a civil war fought from 1455 to 1487 between the House of Lancaster (whose symbol was a red rose) and the House of York (white rose).
Both Lancastrians and Yorkists were descended from the same king (Edward III) and so both sides claimed the throne.
As it happened the Lancastrian side (through Henry VI) inherited the throne. But Henry was unpopular and the Yorkists wanted to get rid of him, so a long war began.
The Wars of the Roses made England weak and nearly bankrupt.
2. (Pubs on the border kept changing names, depending on whether the land they were on had been captured by Lancaster or York. For a while a pub might be called The Red Rose, but then quickly change its name to The White Rose and vice versa.)