[1] As part of a feudal union under German law from 1160—at first under the Saxons—Mecklenburg was granted imperial immediacy in 1348 and its princely rulers styled Dukes of Mecklenburg.

[1][4] However, the dynasty always retained feudal rights to the entire fief and the rulers of both parts of the country always had identical titles,[4] which led to diplomatic confusion.

[5] At the end of the monarchy in 1918, the House of Mecklenburg was the oldest ruling princely dynasty in Germany.

When opportunities arose, for instance upon the death of an emperor, they would seek to seize power; and in 983 Hamburg was destroyed by the Obotrites under their king, Mstivoj.

In 1170 they acknowledged the suzerainty of the Holy Roman Empire, leading to Germanisation and assimilation over the following centuries.

From the 7th through the 12th centuries, the area of Mecklenburg was taken over by Western Slavic peoples, most notably the Obotrites and other tribes that Frankish sources referred to as "Wends".

In the late 12th century, Henry the Lion, Duke of the Saxons, conquered the region, subjugated its local lords, and Christianized its people, in a precursor to the Northern Crusades.

In 1227, Henry Borwin II divided his lands of Mecklenburg among his sons: John received the area called Mecklenburg; Nicholas received Werle; Henry Borwin III Rostock and Pribislaus Parchim-Rinchenberg.

The other parts of Mecklenburg (Parchim, Werle and divisions, Rostock and Stargard) have their own and independent numberings for their rulers.)