The event that sparked the War of the Roses in England was the dynastic conflict between the houses of Lancaster and York, rooted in the struggle for the English throne. The tensions heightened after King Henry VI’s erratic rule, which led to his loss of support and the emergence of rival factions. The initial battles began in 1455, leading to years of intermittent wars that saw changing alliances and bloody confrontations over succession. This civil war had lasting implications for the English monarchy, ultimately contributing to the rise of the Tudor dynasty and reshaping English history.