Complex sentence: Freed of London was established in 1929 by the cobbler Frederick Freed, his wife and an assistant, all of whom had previously been employed by Gamba, a London-based dance shoe maker.
Split into simpler sentences: Freed of London was established in 1929 by the cobbler Frederick Freed, his wife and an assistant. Freed and his wife had both been previously employed by Gamba, a London-based dance shoe maker.