After these years in Leuven, van Roomen went to Würzburg where again he was appointed professor of medicine giving his first lecture on 17 May 1593. Although there was an earlier attempt to found this university, the Julius-Maximilians University of Würzburg was permanently endowed and established in 1582 on the initiative of Prince Bishop Julius Echter von Mespelbrunn (1545-1617). Van Roomen's appointment by Prince Bishop Julius Echter von Mespelbrunn was officially confirmed on the last day of August 1593. It is likely that van Roomen was glad to have an opportunity to leave the Netherlands since there was much unrest and fighting over the Spanish held territory. It was around the end of 1593 that van Roomen married Anna Steeg, the niece of Godefrid Steeg who was the doctor to Prince Bishop Julius Echter von Mespelbrunn. Although he was employed as a professor of medicine, it was mathematics that was van Roomen's real love. However, at Würzburg he did not have as much time to devote to mathematics as he would have liked. Partly this was because his health was poorly and partly it was because of his duties - he was dean of the medical school in 1596, in 1599 and for a third time in 1602. However, he did get involved in some mathematical work.