St. George's Church is one of the oldest sites in Gniezno. Archaeologists discovered remains of a stone mound, which are believed to be an important pagan site until the 10th century - a temple in honour of the Slavic god Niya. After being baptized in 966, Duke Mieszko I chose this symbolic place as his seat, erecting a castle with a chapel on top of the old pagan site. A fragment of the Romanesque wall, exposed on the north and south walls, comes from this period. The structure was burnt down in 1192 during a civil war between Kazimierz II the Just and his older brother High Duke Mieszko III. In its place, the first iteration of the church of St. George was built. Renovated in 1607, a fire in 1613 required its rebuilding in the years 1615-1632. Again, in 1760, it burned down almost completely. Archbishop Antoni Ostrowski, having no funds to rebuild the temple, ordered the church to be demolished. Completely rebuilt and reimagined in a 'baroque' style in 1782, thanks to the efforts of canon Baltazar Pstrokoński and architect Bernard Landwerber, the church has remained with this look ever since. 

On April 25, 1937, the celebration of the 25th anniversary of the Scouts' Banner of Wielkopolska took place on Lech Hill. The celebrations began with a solemn mass in the Church of St. George, during which a marble plaque was dedicated to commemorate the 25th anniversary of Wielkopolska scouting. It was built in the chancel of the church where the service was held. On August 10 of the same year, Bishop Antoni Laubitz, on behalf of the Metropolitan Chapter, handed over the church to the Greater Poland Scouts as a religious center.

On September 7, 1974, Card. Stefan Wyszyński donated the church to the Gniezno seminary. A number of further interior rennovations have taken place since then, most notably, a new floor!