Franciscans have been in Ilok since 1343. In 1349, Duke Ugrin built the current church in the Gothic style, which was dedicated to the Assumption of the Mother of God. The western wing of the monastery was probably built then. In 1454, Nikola Iločki restored the church and monastery by adding a chapel on the north side (today the BDM chapel). After the death of St. Ivan Kapistrano, the church became too narrow, so Nikola Iločki extended it to the east in 1468 and got its current length. The tower was on the front of the church. The Franciscans and the people flee before the Turks to the Pakledin forest. The Turks turned the Franciscan church into a stable, and abandoned the other churches. Then every trace of the body of St. Ivan Capistrano. Even in those difficult times, the Franciscans were active in these regions, and many ended up martyred. After liberation from the Turks, the Franciscans return from Olov (Bosnia) to Ilok. At the provincial chapter in 1700, it was decided that the patron saint of the church would be St. Ivan Capistran.