The Franciscans arrived in Novo mesto in the 15th century. In 1472, they built a monastery next to the Church of St. Leonard on land purchased with donations from the widow Elizabeth Snopčan. The church was replaced with a new one consecrated in 1478 or 1487.
The monastery was partially burned in a fire in 1664, after which it underwent various renovations and extensions over the centuries, including the construction of the convicte in 1696. The monastery library, established at the end of the 15th century, is the oldest library in Novo mesto and also houses incunabula.
From 1746 to 1870, the Franciscans ran a gymnasium that left a significant mark on the city. The tradition of this school is carried on by today's Novo mesto gymnasium.