The first church in this place was erected at the end of the 11th century under the name of Archangel Michael. The chronicler Jan Długosz says that exactly on May 6, 1170 prince Mieszko III the Old and bishop Radwan founded the hospice for wanderers and pilgrims at the church of St. Michael. In 1187, the church and the hospice Mieszko gave to the Knights Hospitallers, who assisted travelers. At the turn of the twelfth and thirteenth century the Order began to build a new church, which after many redevelopments survived to this day. It is one of the first churches in Poland, to which the brick was used. Knights Hospitallers before 1288 changed patron of the church to St John of Jerusalem, however, used the old call in parallel for some time.
At the end of the 15th century the church was damaged by fire. During the renovation, the church was given a gothic character, and around 1512 commander Stanisław Dłuski, added a aisle from the north, erected a tower, and the wooden ceiling was replaced with a vault. Another refurbishment in the years 1719-1740 brought a baroque burial chapel from the south.
In 1832, the Prussian government made a dissolution of the Order, and the church was handed over to the diocese that created the parish. In the interwar years the church was in very poor technical condition, so in 1926 it was renovated. Outside walls were plastered, except for the facade, which retained its medieval character, and the barrel vault from the sixteenth century was replaced by a groin vault. During World War II, the church was turned into a warehouse, which was damaged during the fighting in 1945. During the reconstruction and renovation, the original roman character of the building was restored.
The church is a two-nave building, covered with a sloping roof. Walls support massive buttresses. Its oldest romanesque walls are made in the monk bond. Both aisles are covered with a late gothic stellar vault, and the presbytery has a late romanesque groin vault. It is worth noting the romanesque portal decorated with two columns. One of them during the renovation was set upside down.
Website wikipedia.org, Kościół św. Jana Jerozolimskiego za murami w Poznaniu.