Leiningen is the name of an old German noble family whose lands lay principally in Alsace, Lorraine and the Palatinate. Various branches of this family developed over the centuries and a number of those still exist, including the branch of the Princes of Leiningen.
The first count of Leiningen about whom anything definite is known was a certain Emich II (d. before 1138), whose family became extinct in the male line when Count Frederick, a Minnesinger, died about 1220. Frederick's sister, Liutgarde, married Simon II, count of Saarbrücken, and Frederick, one of their sons, inheriting the lands of the counts of Leiningen, took their arms and their name.
Having increased its possessions, the Leiningen family was divided around 1317 into two branches. The elder of these, whose head was a landgrave, died out in 1467. Upon this event, its lands fell to a female, the last landgrave's sister Margaret, wife of Reinhard, lord of Westerburg, and their descendants were known as the family of Leiningen-Westerburg. Later this family was divided into two branches, those of Alt-Leiningen-Westerburg and Neu-Leiningen-Westerburg, both of which are represented today.
Meanwhile, the younger branch of the Leiningens, known as the family of Leiningen-Hartenburg, was flourishing. On 27 June 1560, this branch was divided into the lines of Leiningen-Dagsburg-Hartenburg, founded by Count Johann Philip (d. 1562), and Leiningen-Dagsburg-Heidesheim or Falkenburg, founded by Count Emicho (d. 1593).
In 1779, the head of the Leiningen-Dagsburg-Hartenburg line was raised to the rank of a Prince of the Holy Roman Empire with the title of Prince of Leiningen. In 1801, this line was deprived of its lands on the left bank of the Rhine by France, but in 1803 it received ample compensation for these losses. A few years later, its possessions were mediatized, and they are now included mainly in Baden, but partly in Bavaria and in Hesse.