Complex sentence: Replicas of the tablets, known as tabots or sellats, are a vital part of the practice of Ethiopian Orthodox Church, which claims that the the original Ark of the Covenant is kept in the Church of Our Lady Mary of Zion in Axum.
Split into simpler sentences: Replicas of the tablets, known as tabots or sellats, are a vital part of the practice of Ethiopian Orthodox Church. That church claims to possess the original Ark of the Covenant is the Church of Our Lady Mary of Zion in Axum.