The foundation of the monastery was made in 1176 by prince Casimir II the Just, who brought monks from the abbey at Morimond in Burgundy and settled them near the crossing of the Pilica River on an old and important route leading from west to south-east. In addition to this ferry, there was also a customs house and market, mentioned in 1145. Initially, the brothers probably lived in temporary wooden buildings until the construction of brick buildings with the church in the first half of the 13th century. In 1232 the Archbishop of Gniezno, Pełka consecrated it to the St. Mary and St. Thomas of Canterbury.
In the thirteenth century, the development of the monastery was hindered by frequent Mongol invasions, so the foundation was surrounded by wooden and earth fortifications, and from the end of the fifteenth century, years of work began on erecting stone fortifications. The Mongol invasion of 1259 especially brought destruction, while the impulse to expand the fortifications could have been the Tatar raid of 1502 on nearby Opatów and the general fear of the Turkish invasion widespread in Central and Eastern Europe during this period.
The monastery supported Władysław I the Elbow-high’s fight with the Czechs, so the prince took special care to the Cistercians, giving them numerous privileges. In 1318, the convent of nobility and knights held at monastery, in which the “Suplex of Sulejów” was proclaimed, asking the pope for the crown to the Władysław. During the reign of king Casimir the Great in the abbey were congresses, four times also visited here king Władysław Jagiełło in the 15th century. Legend tells that knights heading for Grunwald battle sharpened swords on the columns of the church portal.
At the turn of the 15th and 16th centuries, during the rule of the eminent abbot Salomon (1499-1543), Sulejów was expanded and enlarged, both with new monastery ranges and brick fortifications. During the Swedish Deluge in 1656, the Brandenburg army burned a monastery settlement, further destruction caused a fire from 1731. The following years brought the monastery even greater problems, from damages during the Confederation of Bar to the great fire in 1790. The building declined even further because of the dissolution of Cistercian order in 1819. Since then, the process of prolonged destruction of the object has begun, as a result of which the abbots palace and part of the monastery were demolished. Restoration work, renovations and adaptations began in the 20th century, and the Cistercians returned to Sulejow in 1986.
The monastery was situated on a lofty terrace, on the right bank of the Pilica River, which in the 12th century flowed only a few dozen meters south of the abbey. On the eastern side, a small stream of Radońka had its course, while in the north the village of Podklasztorze developed, with its settlement reaching the end of the tenth century.
Built in the first half of the 13th century, the monastery church dedicated to the Blessed Virgin Mary and St. Thomas of Canterbury received the form of an orientated, three-nave, four-bay basilica with a transept and rectangular chancel, built from precisely machined sandstone blocks of considerable size. The opus emplectum technique was used, i.e. the sandstone face of the walls with an average thickness of about 0.9 meters from the inside was filled with rubble and bricks covered with mortar. In the corners of the church between the arms of the transept and the rectangular chancel there are two rectangular chapels measuring 3.4 x 4.5 meters. The nave reached 14.2 x 23.2 meters inside, transept 5.2 x 19.5 meters, and the presbytery reached 6 x 7.6 meters.
In the central part of the west facade a romanesque portal with three columns on each side is placed in the cover protruding in front of the wall. Originally, it had a carved tympanum, after which only the braid decoration has remained. There were two entrances to the aisles: the northern and southern from the cloister. Above the main portal a window with an eight-part rosette of considerable size was pierced, similar cyl