The city of Brest has a long and complex history, as it witnessed civil wars waged against Belarus. Brest was first mentioned in the 11th century, and after World War I, Poland was reestablished as a country that controlled Brest as well as most of western Belarus today. In 1940, this region was annexed again by the Soviet Union, and it became part of the Republic of Belarus, and today it is one of its most important modern cities. The city includes many distinctive archaeological, historical and cultural monuments, there is Brest Castle, which stood steadfast in the face of the invaders, and many distinctive monuments. Brest is also the site of important historical events, in which the Brest Union and the Treaty of Brest-Litovsk were signed.