Tucked away up the hill from Calle Mayor, this intimate little church is Madrid’s oldest surviving building of worship; it is believed to have been built on the site of Muslim Mayrit’s second mosque. The most striking feature is the restored 12th-century Mudéjar bell tower, although much of the remainder dates in part from the 15th century. The vaulting is late Gothic while the fine timber ceiling, which survived a fire in 1936, dates from about the same period.

Despite plateresque and baroque touches, much of the interior is a study in simplicity. The architect Juan de Herrera, one of the great architects of Renaissance Spain, was buried in the crypt in 1597.