In the USSR, cyrillisation or cyrillization (Russian: Кириллиза́ция, romanized: kirillizatsiya) was the name of the campaign from the late 1930s to the 1950s which aimed to replace the writing system based on Latin script (draft of a common alphabet also knowing as Yanalif and Unified Northern Alphabet, which was introduced during the previous latinization program), to one based on Cyrillic.