High Quality Content by WIKIPEDIA articles! The Cathedral of Saint Peter (German: Trierer Dom) is a church in Trier, Rhineland-Palatinate, Germany. It is the oldest cathedral in the country. The edifice is notable for its extremely long life span under multiple different eras each contributing some elements to its design, including the center of the main chapel being made of Roman brick laid under the direction of Saint Helen, resulting in a cathedral added on to gradually rather than rebuilt in different eras. Its dimensions, 112.5 by 41 m, make it the largest church structure in Trier. Since 1986 it has been on the UNESCO list of World Heritage Sites.