Complex sentence: The Manueline armillary spheres appear at the tower's entrance, symbolizing Portugal's nautical explorations, and were used on King Manuel I's personal banner to represent Portuguese discoveries during his rule.
Split into simpler sentences: The Manueline armillary spheres appear at the tower's entrance and symbolize Portugal's nautical explorations. The armillary sphere was King Manuel I's personal banner to represent the Portuguese discoveries during his rule.