Why is magellan said that Earth is round when he completes one revelution over the earth?

People knew the world was spherical long before Columbus and certainly long before Magellan. In any case Magellan never made it. He died in the Philippines having completed a bit more than half the circumnavigation. The person who should get the credit was Sebastian del Cano, Magellan's first mate, who did sail all the way round.