Poznań - Kościół św. Jana Jerozolimskiego za murami

Long before the Christianization of Poland Poznań was an important cultural and political center of the Western Polans. It consisted of a fortified stronghold between the Warta and Cybina rivers. Mieszko I, the first historically recorded ruler of the West Polans and of the early Polish state which they dominated, built one of his main headquarters in Poznań. Mieszko's baptism in 966, seen as a defining moment in the Christianization of the Polish state, may have taken place in Poznań.

Following the baptism, construction began of Poznań's cathedral, the first in Poland. It became the place of burial of the early Piast monarchs, among them Mieszko I, Boleslaus I, Mieszko II Lambert, and Casimir I.

In 1038, Duke Bretislaus I of Bohemia sacked and destroyed both Poznań and Gniezno. In 1138, by the testament of Boleslaus III, Poland was divided into separate duchies under the late king's sons, and Poznań and its surroundings became the domain of Mieszko III the Old.

In 1249, Duke Przemysł I began constructing the Royal Castle on a hill on the left bank of the Warta. Then in 1253, Przemysł issued a charter for the founding of a town under Magdeburg law, between the castle and the river. A large number of German settlers were brought to aid in the building and settlement of the city, which was surrounded by a defensive wall, integrated with the castle.

Poznan was a major center for the fur trade by the late 16th century. Suburban settlements developed around the city walls, on the river islands, and on the right bank, however, the city's development was hampered by regular major fires and floods.

In the 17th century and the 18th, Poznań was affected by a series of wars, attendant military occupations, lootings, and destruction – the Northern Wars, the War of the Polish Succession, and the Seven Years' War. It was also hit by outbreaks of plague, and by floods, particularly that of 1736, which destroyed most of the suburban buildings. The population declined from 20,000 around 1600 to 6,000 around 1730, and Bambergian and Dutch settlers were brought in to rebuild the devastated suburbs.

In 1793, in the Second Partition of Poland, Poznań came under the control of the Kingdom of Prussia.

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The original church on this site was built at the end of the 11th century outside Poznań's medieval defensive walls.

The church is dedicated to St. John of Jerusalem (John the Baptist), the patron saint of the Knights Hospitallers, to whom the church belonged until 1832.

According to Jan Długosz, in 1170 Mieszko III and the bishop of Poznań set up a pilgrims' hospice there. In 1187 the church and hospice were granted to the Order of the Knights Hospitallers. Around the beginning of the 13th century, the Order began construction of a new church, which is essentially the building that survives to this day. It was one of the first brick-built churches in Poland. At some point, the church was re-dedicated to the Order's patron saint,

Following damage in the late 15th century, the church was rebuilt in Gothic style. In 1736 a Baroque chapel was added on the south side. In 1832 the Prussian government abolished the Order, and the church became a parish church.