How did the House of Plantagenet start?

The House of Plantagenet began with Henry II, who ascended to the English throne in 1154 after a period of civil strife known as the Anarchy. Henry was the son of Geoffrey Plantagenet, Count of Anjou, and Matilda, the daughter of King Henry I of England. The dynasty is named after the plant "genista," or broom, which Geoffrey wore in his hat. Henry II's reign marked the start of a powerful royal lineage that would rule England for over three centuries.