After the arrival of the Franciscan monks to Novo mesto, Andrea - the general vicar of Aquilea, the bishop of Ferrara gave the chapel of St. Leonard to the Franciscan order on October 31st 1469. The Franciscans were allowed to tear down the chapel and replace it with a new church that was consecrated in 1478 or 1487. The church in its present state is composed of a narrow longitudinal presbytery with the five sides of an octagon joint, following the Gothic style, as well as a rectangular nave. The church and its roof, ceiling, altars and benches, nearly burnt down in 1664. It was Matija Kastelec (1620-1688), the canon of Novo mesto who was also a writer and an architectural amateur, who designed the vault, the façade and the bell tower of the church. During the following decades, chapels have been added, but the structure remained practically unchanged until 1866, when the main façade was rebuilt in Gothic Revival as designed by the Italian architect Pascoli. The presbytery was painted by Simon Ogrin in 1885-1886, and the nave in 1902 by Matija Koželj from Kamnik. The interior decoration and furniture have been designed in the 18th century - mainly by the Franciscan monks themselves in their own workshop. The wooden Baroque altars were replaced by stone altars in the 19th and early 20th century. The grand white marble altar was built in 1885 by the mason Feliks Toman from Ljubljana. The side altars of the Immaculate and the Coronation of Mary were replaced in 1900 by two altars made of the marble of Nabrežine. The painter Valentin Metzinger has painted both of the altars and the Pieta situated between the chapels. The main altar of St. Francis has been painter by Andrej Herrlein, and the painting of Saint Anthony was made by the Franciscan monk Ladislav Pintar. In the early 20th century, the colourful Gothic stained glass windows were made as well as the wooden pulpit. According to the sources in archives, the numerous tombstones in the church can be attributed to nobility as well as bourgeois families and the patrons of the monastery. Four Renaissance tombstones of noble families were transported from the church in 1867. During the reconstruction of the pavement in 1873, all the tombstones were removed, but a stone plate with a Latin inscription covering the tomb of the canon Matija Kastelec from Novo mesto remained at the left side altar. There is a tombstone of the noble family Raab, the patrons of the monastery, in the chapel of Saint Francis.