 While the baptism of Jesus is very commonly depicted in Early Medieval art, those of the other figures are very rare subjects indeed, and this unusually elaborate and learned programme was no doubt composed with clerical assistance.It does not reflect Byzantine iconographic precedents; instead it matches closely the interest in typology and allegory, of which the influential contemporary Liège-born theologian Rupert of Deutz was a particular exponent (though Rupert was also a particular opponent of the bishop at the time, Otbert of Liège, who took the Emperor's side in the Investiture Controversy).The head of God the Father that appears at the top of the "Baptism of Christ" (identified as PATER) is an early appearance of God the Father in Western art; a Hand of God, more typical of the period, appears in the baptism scenes of Cornelius and Craton.