In 793, Charlemagne sent out Ludger as a missionary to evangelise the M�nsterland. In 797, Ludger founded a school that later became the Cathedral School. Gymnasium Paulinum traces its history back to the school He was ordained as the first bishop of M�nster. The first cathedral was completed by 850. The combination of ford and crossroad, market place, episcopal administrative centre, library and school, established M�nster as an important centre. In 1040, Heinrich III became the first king in M�nster.
In the Middle Ages M�nster was a leading member of the Hanseatic League.
In 1534, the Anabaptists led by John of Leiden, took power in the M�nster Rebellion and founded a democratic proto-socialistic state. They claimed all property, burned all books except the Bible, and called it the "New Jerusalem". John of Leiden believed he would lead the elect from M�nster to capture the entire world and purify it of evil with the sword in preparation for the Second Coming of Christ and the beginning of the Millennium. They went so far as to require all citizens to be naked as preparation for the Second Coming. However, the town was recaptured in 1535; the Anabaptists were tortured to death, their corpses were exhibited in cages, which can still be seen hanging on the Tower of St. Lambert's steeple.
Part of the signing of the Peace of Westphalia of 1648 was held in M�nster. This ended the Thirty Years' War. It also guaranteed the future of the prince-bishop and the diocese; the area was to be exclusively Roman Catholic.
The last outstanding palace of the German baroque period is created according to plans by Johann Conrad Schlaun. In 1780 the University of M�nster (today called "Westphalian Wilhelms-University", WWU) was established, now a major European centre for excellence in education and research with large faculties in the arts, humanities, theology, sciences, business and law. Currently there are about 40,000 undergraduate and
