Complex sentence: Columbia contract player Joe Besser joined as the third Stooge for two years (1956--57), departing in 1958 to nurse his ailing wife, after Columbia terminated its shorts division and released its Stooges contractual rights to the Screen Gems production studio.
Split into simpler sentences: Columbia contract player Joe Besser joined as the third Stooge for two years (1956--57), departing in 1958 to nurse his ailing wife after Columbia terminated its shorts division. The studio then released its Stooges contractual rights to the Screen Gems production studio.