Previously, the University of Leuven (founded 1425) was the preferred place for higher and scientific study in the Low Countries, Universiteit Leiden Degree. But due to the Dutch Revolt , this was no longer possible for students from the northern rebellious provinces. There was therefore a need for a new or replacement university institute in the Northern Netherlands. The university was founded by William of Orange in 1575. At that time it was important for the Northern Netherlands that they could train their own clergy (in the new Protestant theology and in Dutch) and that further well-educated men became available for the country and the national government.

It is assumed that the choice for Leiden was a gift fromWilliam of Orange to the city after Leiden’s relief . He financed the university with confiscated Catholic spiritual properties, such as those of Saint Adelbert’s Abbey, which had been destroyed by the water beggars on his behalf.

It is striking that the foundation letter is in the name of Philip II, replica Netherlands degree. However, at that time, when Philip II still had formal authority over the entire Netherlands, decisions were often made in his name. It was not until 1581 that Philip II had lapsed from the throne in the Placard of Verlatinghe.

The university was initially housed in the Sint Barbaraklooster, but moved in 1577 to the Faliede Bagijnhof on the Rapenburg , to take up residence in 1581 in the confiscated convent of the Dominican White Nuns across the canal, which was demolished in 1616. destroyed by fire, but rebuilt.