Complex sentence: In 456, the Vandals, an East Germanic tribe, coming from North Africa, occupied the coastal cities of the island; they imposed garrisons guarded by African auxiliaries, like the Mauri.
Split into simpler sentences: In 456, the Vandals, an East Germanic tribe, coming from North Africa, occupied the coastal cities of the island. The Vandals imposed garrisons guarded by African auxiliaries, like the Mauri.