Why was Richard the third in battle with Henry Tudor?

Richard III and Henry Tudor (later Henry VII) were in conflict primarily due to competing claims to the English throne. Richard's reign was marked by instability and discontent, leading to opposition from those who supported Henry's claim, rooted in his Welsh ancestry and descent from the royal line. The culmination of this rivalry was the Battle of Bosworth Field in 1485, where Richard was defeated, leading to the end of the Plantagenet dynasty and the rise of the Tudor dynasty. This battle was pivotal in reshaping the political landscape of England.