The Diocesan Museum in Trier (Diözesanmuseum) is housed in a 19th century building which was formerly a prison. The building is opposite the Dom cathedral and can’t be missed. Here many priceless works of art and religious artefacts are on display – most of which came from the Dom. The earliest work of art is a ceiling painting from the imperial palace which once stood where the cathedral is today, dating to the 3rd century. There are also 9th century paintings from the reconstructed crypt of the church of St. Maximin.