Borderland residences, due to their location, the political situation of the country and the resulting military value of the architecture, have repeatedly gained great importance in the history of the Republic. The residence in Mikulińce, erected on the river Seret, on one of the main routes, was one of these buildings. The castle walls witnessed important historical events and the presence of prominent Poles - among them hetmans and magnates related to them. The history of the resort itself was crucial to the establishment of the residence. Mikulińce was mentioned in sources as early as the 11th century. Development in the following centuries was constantly hampered by Tartar incursions, which made it all the more important to build and modernise fortifications to ensure the safety of the town and its inhabitants.

Hetman's stronghold
The history of the walled fortress goes back to the mid 16th century and is connected with the figure of Anna of Sieniawski, the wife of Krakow castellan Wawrzyniec Spytek Jordan. The noblewoman chose an area for the construction of her residence which was of great defensive value - a hill located in a bend of the river. After the Jordans, the estate was taken over by the Zborowskis (who treated the local castle as their main family residence), from whom Great Crown Hetman Stanisław Koniecpolski bought Mikulińce in 1637. Both the eminent commander and his son, Aleksander, made investments to renovate and modernise the castle, which performed its defensive functions well. The stronghold was given a regular rectangular plan, with walls surrounding the inner courtyard, to which two gates with vaulted passages led - the western (main) and eastern ones. At the corners were towers of circular plan, two of which (north-west and south-east) towered over the building. At the western line of the ramparts was the main residential building. The architectural form retained a military character and shooting holes were visible on the walls. Aleksander Czołowski noted two centuries later that the building "counted (...) among the more beautiful and stronger castles in these parts" ("Teka konserwatorska" 1892).

The successive owners of the castle, which passed successively into the hands of the Lubomirski, Sieniawski and Potocki families, held an equally high socio-political rank as the Koniecpolscy. In the 18th century, the fortalice gradually lost its military significance, which contributed to its subsequent deterioration and the construction of a new residence in Mikulińce - a classicist palace. The decision to change the place of residence was made by Ludwika Potocki, née Mniszech (widow of Grand Hetman of the Crown and castellan of Kraków, Józef Potocki). At the same time, the magnate showed concern for the state of the estate, e.g. by obtaining confirmation of the municipal rights from King August III Sas, and by founding a church and a monastery of missionary priests in Mikulińce.

In the service of industry, or the 19th century fate of the castle
The next important stage in the history of the fortalice came under the Konopek family, who bought Mikulińce from Ludwika of Mniszechs' nephew, Józef Potocki. They wanted to make the town (along with the surrounding villages) an important industrial centre, establishing, among other things, a distillery and manufactories. An important way of development was also to give it a spa function, provided by a bathing establishment. New roles were also assigned to the castle complex itself, adapting the former residence of the Koniecpolskis for use as a cloth factory and lace-making workshop. After the family in question, as a result of the marriage of Józefa Konopkówna, the estate was taken over by Mieczysław Rey. The lack of thorough renovations and the introduction of mundane functions in the following decades (e.g. by converting part of the complex into stables) caused the condition of the building to deteriorate considerably. The castle has not regained its splendour, but the old, 17th-century character of the building remains legible; moreover, some of the rooms are still in use and serve as flats.