Battle Abbey: William commissioned the construction of Battle Abbey in East Sussex, England, to commemorate his victory at the Battle of Hastings in 1066. The abbey was built on the site where Harold II, the last Anglo-Saxon king of England, fell during the battle.
Church of St. Stephen, Caen: William also founded and funded the construction of the Church of St. Stephen in Caen, Normandy, France. This church was built in the Romanesque style and served as a monastery for the Benedictine monks.
Westminster Abbey: Although not directly constructed by William the Conqueror, he did contribute to the rebuilding and expansion of Westminster Abbey in London. The abbey became a significant royal church and the traditional coronation site for English monarchs.
It's worth noting that the building and patronage of churches and religious institutions were common practices among medieval rulers as a way to demonstrate their piety, secure divine favor, and consolidate their power.