The oldest church in Pest, built in the 12th century in Romanesque style on the site of the grave of martyr Bishop Gellért. Nothing remains of the original church; over the centuries it took on Gothic features, and during the 17th century it was used by the Turks as a mosque. Following a fire in 1723 it was rebuilt in Baroque style, but the interior has neo-Classical features too. Main sights: Gothic chapel, neo-Gothic carved pulpit, 15th century Italian frescoes and 20th century main altar.