The underlying cause of the War of the Roses, which lasted from 1455 to 1487, was rooted in the dynastic struggle between the rival houses of Lancaster and York for the English throne. Both factions were descendants of Edward III, but political instability and civil strife arose after the weak reign of Henry VI, who suffered from mental illness. The conflict was fueled by issues of succession, power struggles among nobility, and grievances over land and influence. This internal strife led to a series of battles and shifting allegiances, ultimately resulting in the rise of the Tudor dynasty under Henry VII, which concluded the conflict and established relative stability in England.