The Treaty of Ribemont was signed on 2 May 1179 by the two eldest sons of the late Duke Matthias I of Lorraine.
[2] Through the mediation of Count Philip of Flanders the next year, the brothers were able to reach an agreement at Ribemont to partition the duchy.
Simon received the southern, French-speaking part of the duchy, and Frederick received the northern, German-speaking part plus Ormes and Gerbéviller.
Frederick also pledged himself to be his brother's vassal, but he employed the title "Duke of Bitche", an expression of equal status.
[2] In 1206 Simon abdicated and the duchy was reunited in the hands of his brother, as per the treaty of 1179.