Complex sentence: Above the high altar is a canopy ("ciborium") on columns decorated with fine reliefs; the altarpiece is the famous Pala d'Oro, a masterpiece of Byzantine craftsmanship, originally designed for an antependium.
Split into simpler sentences: Above the high altar is a canopy ("ciborium") on columns decorated with fine reliefs. The altarpiece is the famous Pala d'Oro, a masterpiece of Byzantine craftsmanship, originally designed for an antependium.