Why were they fighting in bosworth?

The Battle of Bosworth, fought on August 22, 1485, was a pivotal conflict in the Wars of the Roses, a series of dynastic struggles for the English throne between the houses of Lancaster and York. The battle pitted King Richard III of York against Henry Tudor, a Lancastrian claimant. The fight was driven by a struggle for power, as Henry sought to dethrone Richard and establish his own rule, which ultimately led to Richard's defeat and Henry's ascension as King Henry VII, marking the start of the Tudor dynasty.