England
The Wars of the Roses
The Wars of the Roses are so called because tradition holds that the House of York bore a white rose as its symbol and the House of Lancaster bore a red rose, and it was these two families who drove England into twenty years of civil war. The plain fact is, these were the symbols of neither house, but were associated with them by later writers. No one at the time spoke of a war between roses.
However fictional the roses, the wars were real enough. They encompassed not only the two families of York and Lancaster, but gathered in all the great clans of England and at one time or another dragged Burgundy, France, Scotland and Wales into the conflict. The battles were not especially large, even by the standards of the day when armies were much smaller anyway, but as with all civil wars they tended to be bloody and vicious, and no matter who won a battle it was mostly Englishmen who died. Also as is common in civil wars, many families were destroyed and much property and other wealth changed hands, often more than once, so that a list of who ruled England in 1500 was quite different from a list made in 1450.
After all the strife and struggle, who won the Wars? The answer is: both and neither. To understand that answer, you'll just have to read through all the grim details.