Fortified settlement existed here in the early twelfth century. The first castle in Uniejow certainly was already in 1331 when it was damaged by the Teutonic Knights. There is no assurance, however, that stood in the place of what later assumption. About half of the fourteenth century archbishop of Gniezno Jarosław Bogoria Skotnicki erected in its present location a new lock on an artificial small hill. It was founded on a rectangular plan with sides of 23x29 meters, which from the outside of the eastern wall dostawiona was a round tower with a diameter of 9 and a height of 25 meters. The gate was in the curtain wall of the south, and the west wing were the only living - trzykondygnacjowy building divided into two chambers in the lowest level. With the building in the courtyard stood a small chapel.

  The castle housed a library and archive archbishop, is also organized reunions and local councils sieradzki province.

In 1381 years, Bernard won the stronghold of Grabow, walls do not hit much, but the equipment was destroyed. About half of the fifteenth century the castle was enlarged by surrounding the second circuit of the walls, slightly lower than the original. At the corners of the residential wing in międzymurzu stood two square residential towers, as well as the earlier building also trzykondygnacjowe. Gate was replaced with a square gate tower.

In 1492 during the War of Koźmin the castle was captured by Lawrence Kosmider Gruszczyński. After the devastation of this period and a fire in 1525 the castle was rebuilt by the Stanislaus Gomolina, who drew attention has mainly representative functions assumptions. Without changing the existing buildings added a cranked wing of the south-east, which joined the round tower of the Gatehouse.

In the years 1627-1638 the castle was owned by John Wężyk, then for 1652 years - Maciej Łubieński. Reconstruction made ​​by them gave the mansion its present appearance by the extension of the south wing to the corner of the tower. From this era comes the portal gate. Performed after repair work has not changed the shape of the episcopal residence. Among other things, the work undertaken following the destruction of the Swedish wars of the period, after the invasion of the Saxon army in 1704, and later by Christopher Anthony Szembek.

At the end of the eighteenth century, the castle was partially abandoned after the secularization of church property seized by the Prussian state. In 1836, he received his General Alexander Toll. During the renovation carried out by his descendants in the mid-nineteenth century western section of the wall between the old corner towers was replaced with a terrace and park was created przyzamkowy. It preserves the overall shape of assumptions, but given the castle walls Classical features, only the round tower has retained our original Gothic appearance.

After the First World War the castle decorated guest house. War has left a massive destruction, but in the years 1956-1967 assumption completely rebuilt and decorated in the hotel, which is located here today.