 The Romanesque movement, which went from approximately 800 AD to 1100 AD, was one of the most fruitful and creative periods in Italian architecture, when several masterpieces, such as the Leaning Tower of Pisa in the Piazza dei Miracoli, and the Basilica of Sant'Ambrogio in Milan were built.It was known for its usage of the Roman arches, stained glass windows, and also its curved columns which commonly featured in cloisters.The main innovation of Italian Romanesque architecture was the vault, which had never been seen before in the history of Western architecture.