The 'Constitution of Medina' is probably the first legal document of Muhammad and dates back to the first year after his hijra (622 CE), or "emigration", which brought him from his hometown Mecca to the cluster of towns known as Yathrib or Medina in the Hijaz (northern Arabia) and marked the beginning of the Islamic era. Muslim historians and jurists have been familiar with this important document for centuries, and aware of its legal and theological implications for Islamic law. It was first brought to the attention of scholars in the West at the end of the 19th century by Wellhausen, who accepted it as an authentic document from the time of the Prophet. Since then, such leading orientalists as Goldziher, Gil, Serjeant, Goto, U. Rubin and J. B. Simonsen have studied various aspects of it. This monograph offers an edited translation and interpretation of the earliest and most important document from the time of Muhammad. Lecker's focus is on the Jewish tribes, the Treaty of the Mu'minun and the Treaty of the Jews..