Answer
Yazid I ascended to the caliphate as a result of the succession plan orchestrated by his father, Muawiya I. Muawiya I, the founder of the Umayyad dynasty, deviated from the traditional elective system for selecting caliphs and designated Yazid I as his successor. This move marked a significant departure from the Rashidun caliphate and had lasting ramifications on the political landscape of the Islamic world.