Records of the existence of a Franciscan monastery in Osijek in the pre-Turkish period are not historically confirmed. Although there are traditional stories of Franciscans in the nearby village Anitno, there are no existing proofs of any Franciscan monastery on that locality to this day. After Turkish defeat in Vienna 1683, and the victory of the Christian army at Nagy Harsany on 18 August, 1687, Slavonia was liberated, and so was Osijek, where the Franciscans instantly took up residence.
They settled and remained to this day in the oldest part of the town, Tvrđa. In the first ten years their living conditions were very poor. They had one poor apartment which P. Simon from Vienna moved into back in 1687. They had no finances to build a bigger monastery, while up to 1692 the area wasn't perfectly safe. In 1699, thanks to endeavours of P. Pavle from Rama, the Franciscans took up building the original monastery with two wings – eastern and southern – in the shape of the letter "L". The construction works lasted till 1705. A year later the monastery was officially founded. Guardian P. Petar Osječanin enlarged it, and P. Martin Osječanin built two more storeys.