Complex sentence: Anthemius lost his allies and, with the imperial treasury almost emptied by the failed operation, renounced taking Africa back and concentrated on the second problem of his Empire, keeping under his control the Western provinces that were the target of Visigoth expansion.
Split into simpler sentences: Anthemius lost his allies and, with the imperial treasury almost emptied by the failed operation, renounced taking Africa back. Instead he concentrated on the second problem of his Empire, keeping under his control the Western provinces targeted by Visigoth expansion.