Fita (Ѳ, ѳ) is a letter of the early Cyrillic alphabet, descended from the Greek Theta. It was mainly used to write proper names derived from Greek. Since the Slavs would pronounce these names with an "f" sound instead of the proper sound which is like English "th" -- for example "Theodor" would be pronounced as "Fyodor" -- it was replaced by the letter Ef (Ф, ф) in 1918.
Fita is not to be confused with the similar-looking vowel letter (Ө, ө ), which is currently used in Kazakh and Mongolian.
