Before 1945 the town was a district of Frankfurt (Oder) (Dammvorstadt) and it belonged to Prussia, Brandenburg Province, Frankfurt (Oder) administrative district, urban county – Frankfurt (Oder). Until World War II it was a district of Frankfurt - situated on the other side of the Oder River, officially called Dammvorstadt (embankment suburb) or popularly Gartenstadt (garden town).
The area of today’s Słubice known as the village, Sliwice, might have been already mentioned in the 11th century. However, the first mention of the land situated on the right embankment of the Oder River comes from the 13th century. In 1253, margrave John I from the Askanien line granted Frankfurt a town charter. In the document from 1253 there is also a mention that the commune governor of Frankfurt is also entitled to the land on the right bank of the Oder River, known also as Zliwitz. Since that time the history of Słubice has also been the history of Frankfurt [see the plan of Frankfurt (O) no 2 and 3].
In 1430, the dynamically developing town joined the Hanseatic League, which was an alliance of trading cities along the coast of Northern Europe, but was a member for only about 100 years. During the Hussite Wars the town was partially burnt down. In 1506, the University of Viadrina was founded in Frankfurt and it existed until 1811. In 1517, Martin Luther presented his theses, the then university vice-chancellor, Konrad Wimpin, responded to them with his antitheses. Many students left Frankfurt then and went to Wittenberg. The university regained its importance only after the end of the Thirty Years’ War. Among the people who studied here there were: Carl Philipp Emanuel Bach, Aleksander von Humboldt, Wilhelm von Humboldt and Heinrich von Kleist.
During the Thirty Years’ War the Swedes plundered the town, and the plague, which broke out shortly afterwards decimated its inhabitants. At the end of July 1759 during the Seven Years’ War the Russians entered Dammvorstadt (Słubice) and after a short gunfire they retreated, but the town had to pay them a contribution of 600 thousand thalers. In 1785 during the spring flood of the Oder River forced its way through the embankment and flooded the whole of today’s Słubice. As a result one person died. During the Napoleonic wars Frankfurt became the garrison for the army of Napoleon. In 1813 the retreating Napoleonic army burnt the bridge over the Oder River in fear of the Russians. In 1816 the town became the seat of the government for the newly established administrative district Frankfurt (Oder) and for the district supreme court.
Frankfurt has already been an important trading centre since the Middle Ages. In the mid-19th century a metal industry developed, a gasworks factory was established and Frankfurt gained a railway connection with Berlin After World War I in 1923 it became the seat of the eastern railway management. At the end of the 19th century the first stone bridge over the river Oder was consecrated. Since 1891, a telephone network was already in use in Frankfurt.
In 1933 the national socialists were elected into power. The town did not suffer great damage during World War II as there were no important industrial and military layouts here. Frankfurt was only destroyed in April 1945 by invading Russians. The retreating Germans blew up the bridge over the Oder River and the Soviet army occupied Dammvorstadt without fighting. After the war by the resolution of the Potsdam Agreement, Frankfurt was divided into two parts and became a border town. The German population from Dammvorstadt had to leave their houses. The new town was created – Słubice. Since that time, the history of the divided town has run in two directions. In 1949 Frankfurt became part of the German Democratic Republic. The reunification of Germany in 1990 led to another rapprochement of the two towns.
After the end of military activities in 1945 the Polish administration was beginning to form in the newly founded Słubice. At the end of 1945 Słubice had 685 inhabitants. With the passing of time the town was chosen for the seat of Rzepin County, a few years later transformed into Słubice County, which existed until 1975. In 1972 a border crossing was opened and Słubice began co-operation with Frankfurt (Oder). The dynamic development of the town was observed only after the system changes in 1989 – the town gained a new face then.
In 1991 in Frankfurt there was a reactivation of the university, which acquired a new character as the European University of Viadrina. Among other things, its aim is being multicultural and about 30% of students are Poles. In 1994 the first Polish dormitories were built on the Polish side and in 1995 the works began on Collegium Polonicum, which was put into use in 1998. In 1999 Słubice County was re-established.