Complex sentence: He called on Pope Sixtus IV, pleading for a common crusade, but although the pope acknowledged his merits, by naming him "the Athlete of Christ", but no anti-Ottoman coalition materialized.
Split into simpler sentences: He called on Pope Sixtus IV, pleading for a crusade. Although the pope acknowledged his merits, by naming him "the Athlete of Christ", no anti-Ottoman coalition materialized.