In 1103, Moresdörf had its first documentary mention when the Ravengiersburg Monastery received one fourth of the village's tithes from St. Stephan in Mainz.

In 1359, the whole tithe belonged to the noble knight Colin von Senheim and his wife, who enfeoffed the Electorate of Trier with it.

A grand new building was built in 1768 by Paul Stehling[3] Beginning in 1794, Mörsdorf lay under French rule.

The municipality's arms might in English heraldic language be described thus: Quarterly per saltire argent and sable, in chief a cross engrailed gules, surmounted in chief by a label of three points of the second, dexter a cramp bendwise of the first, sinister a palm leaf palewise Or, and in base issuant from base on a pedestal a cross bottony of the third.

The cross engrailed (that is, with wavy or sawtoothlike edges) refers to the noble family Beissel von Gymnich, who still had holdings in Mörsdorf as late as 1744.

The charge on the dexter (armsbearer's right, viewer's left) side, known as a cramp, or crampoon, in English heraldry, and a Maueranker in the German blazon (a "wall anchor", which is likewise what a cramp is held to be in English heraldry,[6] but not always in German[7]), is drawn from the arms formerly borne by the Lords of Metzenhausen.