"Müstert" comes from the Latin word "monasterium" and is probably a reference to the fact that already in the 6th/7th century, there was a church centre here. This centre probably grew in importance during the first phase of proselytization and Christianization in the region and was later the head office of pastoral care in the districts of Piesport, Emmel and Müstert. It was not so much a monastery but rather a clerical community. There was a similar institution in the area on the left side of the lower Mosella. In the first half of the 7th century, a "monasterium" was established as a church centre on the Maifeld (Münstermaifeld). It is highly likely that the Monasterium-/ Müstert parish was destroyed during the Norman invasion at the beginning of the year 882 and that its functions were assumed by the local churches of Emmel and Piesport during the reconstruction works. We know from old documents, that Müstert was called Munster in 1055, Munstre in 1098, Monasterium in 1179 and Münster at the beginning of the 19th century. Since the early 12th century, the Mettlach/Saar monastery is the seignior and holder of the patronage and tithe rights with an additional estate in Piesport. In 1102, the clergyman Ernest bequeathed his entire property in Münster = Müstert to the monastery. There are several records relating to the legal status of this estate since 1488. In Napoleonic times, serfdom was abolished and the estate, which was occasionally called Marienhof, was auctioned with all its goods for 2566 thaler.