Belarusian is an Eastern Slavic language with about 7.5 million speakers in Belarus. It is closely related to Russian and Ukrainian.
The country now known as the Belarus was part of the Grand Duchy of Lithuania from the mid-13th century until the end of the 18th century. An archaic form of Belarusian known as "Old Belarusian" was the official language of the Grand Duchy and was initially written with the Cyrillic alphabet. Due to the domination of the Greek Orthodox Church in the region, the written form of Belarusian was heavily influenced by Church Slavonic, the liturgical language of the Orthodox Church.
The Russian invasion of 1654-1667 caused to the destruction of many Belarusian cities and the deaths of about half the population, including 80% of the urban population. By 1710, Old Belarusian was replaced by Polish as the official language of the region; however Belarusian continued to appear in writing in a limited way. During the late 19th century, Belarusian, written in the Latin alphabet, started to emerge as a literary language closer to its modern form. It took many years for people to agree on a standard spelling system: some favored Polish-based systems; some preferred Russian-based systems and others used systems based on the Belarusian version of the Latin alphabet. Eventually a compromise was reached which combines elements from all these systems. It was during this time that Belarusian started to be written with the Cyrillic alphabet as well.