In 1112 the village church was founded, of which the romanesque tower still survives as the oldest monument of Le Plessis. At the end of the 12th the village was renamed Le Plessis-Raoul, after the local lord Raoul, chamberlain of king Philip II of France. In 1407 it came into the hands of Jean Piquet de La Haye, who built a castle in the village, now called Le Plessis-Piquet.