Romanesque architecture developed in medieval Europe between the 6th and 12th centuries. It was characterized by semi-circular arches and massive stone walls. Common features included thick walls with small windows, semi-circular arches over doors and windows, paired arched openings separated by pillars, and piers made of masonry to support arches. Interior structures like arcades, vaults in different forms like barrel and groin, and wooden roofs were also used. Important structures associated with Romanesque architecture included baptistries, cloisters, porches, and crypts.