Among the city's Roman monuments are the Porta Nigra (early 4th cent.), an imposing and well-preserved fortified gate; an amphitheater (c.100), which can seat about 25,000 persons; ruins of the imperial baths (4th cent.); and the basilica (probably built in the early 4th cent.; now a church). Trier also has a Romanesque cathedral, built (11th–12th cent.) around a 4th-century nucleus and containing the Holy Coat of Treves (supposed to be the seamless coat of Jesus). Other noteworthy buildings include the Gothic Church of Our Lady (13th cent.; Ger. Liebfrauenkirche ); the baroque electoral palace (17th–18th cent.); and the baroque Church of St. Paulinus (1732–54; designed by B. Neumann). The rare exhibitions (e.g., in 1844, 1891, 1933, and 1959) of the Holy Coat of Treves have been the occasions of large pilgrimages. The remains of St. Matthew are preserved in a shrine in the pilgrimage church of St. Matthew (built in the 12th cent. around an earlier Benedictine monastery). Trier also has a theological seminary, a school of viticulture, and several museums, including one in the house where Karl Marx was born (1818).