Olesko Castle (ukr. Олесько) is one of the buildings with a long and rich history, connected with the history of the First Republic. It is located in the Lviv region, Busko district, Ukraine. Olesko was one of the oldest settlements and castles of the Halicz-Volyn principality. In 1327, the local 'castrum' was mentioned as the property of the Halicz-Volhynia prince Bolesław Jerzy II Trojdenovic. It is not known, however, whether the fortress already had any masonry elements at that time. From 1340, Olesko remained under the rule of the Lithuanian dukes. In 1366, it was annexed to Poland by King Casimir the Great. It then came under the rule of Louis of Hungary and, after his death, under the rule of Lubart, Duke of Lutsk. In 1432, Władysław Jagiełło, after taking Olesko from his brother, Duke Świdrygiella, granted the castle on lease to Jan of Sienna. In 1441, Władysław Warneńczyk gave the castle, together with the town and belonging villages, to the Sieniński family "for ever and ever". It remained in the hands of this family until the beginning of the 16th century. In 1511, after the death of the last male representative of the Sienińskis of Olesko, Piotr, his daughters divided up the patrimony. The elder sister, Anna, married to the starosta of Bytom, Fryderyk Herburt, received the right-hand part of the castle, while the younger sister, Jadwiga (married to Marcin Kamieniecki, Voivode of Podolia), received the left-hand part. The gate, the courtyard, the well and the wooden croft by the castle remained in common. In 1557, the right side of the castle was inherited by the Daniłowicz family. In 1580, the Kamienieccy sold their half to Stanislav Żółkiewski, field hetman and then Grand Hetman of the Crown, killed at Cecora. In 1605, the widowed Jan Danilowicz married the hetman's daughter, Zofia, receiving half the castle in Olesko as dowry, thus putting the stronghold back in the hands of one family. Jan took advantage of this fact by thoroughly rebuilding his residence. In 1627, Jan Daniłowicz's daughter, Teofila, married Jakub Sobieski. It was at the Olesko castle, while Teofila was staying with her mother Zofia, that their second son, later Hetman and King of Poland, Jan Sobieski, was born on 17 August 1629. In 1637, after the extinction of the male representatives of the Daniłowicz family, the entire Olesko estate passed to the Sobieskis. However, they did not permanently reside in the castle, which was let out on pawn during the 17th century. At first, it was held by the Wiśniowiecki family, while in the 1760s Olesko with its castle found itself in the hands of the Sobieski family. Olesko with the castle fell into the hands of the Koniecpolskis. However, as the 1664 inventory shows, they were not interested in improving the condition of the residence. Neither were the lessees interested in defending the castle, which had been plundered several times during battles with the Cossacks and Tatar and Turkish invasions. It was not until Jan Sobieski, already as King of Poland, renovated his birthplace with his wife. In 1719, Jan III's eldest son, Jakub Sobieski, sold the key of Olesko together with the castle to the Rzewuski family. Under Wacław Rzewuski, residing permanently in Podhorce, the building once again fell into decline. This state of affairs was not changed by the subsequent owners of Olesko, the Zielińskis and the Lityńskis.

The castle was built of stone and brick on a lonely, steep hill, surrounded by marshland. Its origins have not yet been convincingly explained. It is believed to be one of the oldest castles in the territory of present-day Ukraine, as the masonry defence structure may have been built as early as the first quarter of the 14th century. The oldest elements of the castle are the defence perimeter, built on an irregular ellipse plan, and the quadrilateral gate tower. The appearance of the residential part of the castle remains unclear; it may have been a residential tower. Further transformations of the building in the Middle Ages are insufficiently recognised. It is not known whether any alterations were made to the fortress by the descendants of Jan of Sienna. In 1512, after the Tartar invasion which was tragic for Olesko, one of its then co-owners, Fryderyk Herburt, received permission from King Sigismund I the Old to allocate the tenons of two quarters to 'transform' the castle ('pro reformando fortalitio'), but it is not known whether he managed to carry out any work before his death in the battle of Sokal on 2 August 1519.

Thanks to a detailed inventory from 1664, however, we can reconstruct the state of the foundation after the reconstruction by Jan Danilovich. In front of the castle there was an outpost, protected by wooden fortifications ("spurs"). Within the castle's perimeter there were auxiliary buildings (e.g. the house of the chief keeper, stables, bakery, malt-house), as well as an orchard and an "Italian" garden. The castle hill itself was surrounded by earth ramparts, additionally protected by two ponds, one in front of the entrance gate and the other at the back of the building. The entrance to the chateau led across a bridge supported by brick arcades, with the last span a drawbridge. A plaque with the Danilovich coat of arms was built in above the gate. Adjoining the tower to the east was a quadrilateral building, protruding from the face of the medieval defensive perimeter, three storeys high, housing two dwellings on each level. The internal accommodation consisted of two two-storey, semi-oval wings, built into the oval of the medieval defensive perimeter. They were separated by a small quadrangular courtyard with a well. The living rooms, although already badly damaged at the time of the inventory, were richly decorated, had partially marble floors, and were heated by tiled cookers (one of which was "Turkish-made") or fireplaces. The large dining room was decorated with images of Polish rulers, and the residential flats were also painted "from top to bottom" or at least "with red-painted carpentry fascias". The interior furnishings included a "black marble table on wooden balusters". The castle also had a vaulted St Anne's chapel, "with a very beautiful golden casting on the top" and a "golden" main altar. The ancillary buildings included a cekhauz, kitchens and larders, as well as "patiaries" and a "great dungeon".

The castle was renovated during the reign of Jan and Maria Kazimiera Sobieski. This mainly concerned the interior decoration, especially of the castle chapel, with the creation of al fresco wall paintings. The queen also renovated the castle garden and de-silt the overgrown ponds. Further work on the castle was carried out by the voivode of Volhynia, Seweryn Józef Rzewuski. Again, these concerned interior decoration (stuccowork, sculptures, wall paintings), and Rzewuski also founded a park on the slopes of the castle hill, which was decorated with sculptures by Józef Leblas, among others. However, his brother and successor, Grand Hetman of the Crown and Castellan of Cracow, Wacław Piotr Rzewuski, moved most of the castle's furnishings to his residence in Podhorce. Since then, the castle has gradually deteriorated, as successive owners either took no interest in it or did not have the strength or resources to look after it properly.

In 1882, as the bicentenary of the relief of Vienna was approaching, a civic committee was formed to buy the castle from its then owner, Zofia Lityńska, with a view to handing it over to the nation as a valuable memento of John III. Soon afterwards, restoration work began, including strengthening and stabilising the sloping walls with buttresses, repairing the roofs, ceilings and floors, and restoring the wall paintings and stuccowork . Unfortunately, during the First World War, the castle was a place of accommodation for Russian soldiers, who devastated and ransacked the newly renovated interiors, not only carrying away valuable movable property, but also intentionally destroying, for example, the 18th century wall paintings and the fireplace with the "Judgement of Paris" figural group. Reconstruction was undertaken in the 1930s under the direction of Alfred Majewski. The castle was devastated again during World War II, and reconstruction and partial restoration were not undertaken until the 1960s. Today the castle houses a branch of the Lviv Art Gallery.