In the current administrative division of Poznań, Ostrów Tumski is part of an osiedle which also includes the neighbourhoods of Śródka, Zawady and Komandoria, all on the east side of the river.
In the 10th century the settlement on the island became one of the main political centres of the Piast domains, which in turn formed the hub of the early Polish state.
Archaeological work carried out in 1999 revealed that the ducal palace stood on the site now occupied by the Church of the Virgin Mary (west of the cathedral).
With the Polish ruler's adoption of Christianity the state received its first missionary bishop, Jordan, who is believed to have made Poznań his seat.
At the start of the 11th century the settlement was rebuilt (and enlarged) after suffering destruction caused by a flood, one of many which would periodically affect Poznań throughout history.
It was rebuilt under Casimir I the Restorer, but the country's capital was now moved to Kraków, and the Greater Poland settlements of Poznań and Gniezno lost their primary political importance.
With the building of the Royal Castle and the walled city of Poznań on the left bank of the Warta in the second half of the 13th century, Ostrów Tumski became the exclusive domain of the bishops.
In the 19th century, the Prussian authorities aimed to make Poznań into a fortress city by surrounding it with defensive fortifications; the Warta and Cybina rivers played an important part in these plans.
Ostrów Tumski suffered damage in the Battle of Poznań (1945), when the Red Army captured the city from its Nazi German occupiers.
Ostrów Tumski today contains the cathedral and associated ecclesiastic buildings in the central part of the island, the residential neighborhood of Zagórze to the south (including an estate of communal houses dating from the 1920s), and a cogeneration plant and other industrial areas in the north.