Complex sentence: At the time of Sierra Leone's independence in 1961 from the United Kingdom, the monetary system was controlled by the West Africa Currency Board, which issued the West African Pound, a colonial currency tied to the Pound Sterling.
Split into simpler sentences: At the time of Sierra Leone's independence in 1961 from the United Kingdom, the monetary system was controlled by the West Africa Currency Board. The WACB issued the West African Pound, a colonial currency tied to the Pound Sterling.