Complex sentence: Some of his patrons claimed divine descent, such as Diagoras of Rhodes, but Pindar considered men to be akin to gods if they realized their full potential: their innate gifts were divinely bestowed, and even then success depended on the gods' active favour.
Split into simpler sentences: Some of his patrons actually claimed divine descent, such as Diagoras of Rhodes. Those whose lineage was not so exalted could still reveal their likeness to the gods by realizing their full potential, since men's innate gifts were divinely bestowed, though even then success depended on the gods' active favour.