The Baptistery, dedicated to St. John the Baptist, stands opposite the west end of the Duomo. The round Romanesque building was begun in the mid 12th century: "1153 Mense August fundata fuit haec" ("In the month of August 1153 was set up here..."). It was built in Romanesque style by an architect known as Diotisalvi ("God Save You"), who worked also in the church of the Holy Sepulchre in the city. His name is mentioned on a pillar inside, as "Diotosalvi magister". the construction was not, however, finished until the 14th century, when the loggia, the top storey and the dome were added in Gothic style by Nicola Pisano and Giovanni Pisano.