Complex sentence: Mauretania and western Numidia were annexed by Rome in 40 AD, made a Roman Province in 43 AD and later enlarged with the name of Mauretania Tingitana ad Mauretania Caesariensis.
Split into simpler sentences: Mauretania and western Numidia were annexed by Rome in AD 40, and became a Roman province in AD 43 AD. This was later enlarged under the name of Mauretania Tingitana ad Mauretania Caesariensis.