Complex sentence: The Sherman family sold the museum's collection in 1999 to a Canadian entrepreneur, William Jamieson (died July 3,2011) a collector and dealer of tribal art with an impressive collection of shrunken heads, among other curiosities.
Split into simpler sentences: The Sherman family sold the museum's collection in 1999 to a Canadian entrepreneur, William Jamieson. Jamieson was a collector and dealer of tribal art with an impressive collection of shrunken heads among other curiosities.