The Calling of St James to the Apostleship appears to be Mantegna's design, partially carried out by Pizzolo; the subjects of St James baptizing, his appearing before the judge, and going to execution, and most of the legend of St Christopher, are entirely by Mantegna.
Armed with it he passed safely into heathen Germany and began a systematic crusade, baptizing, overturning idols, founding churches and monasteries, and calling from England a band of missionary helpers, monks and nuns, some of whom have become famous: St Lull, his successor in the see at Mainz; St Burchard, bishop of Wurzburg; St Gregory, abbot at Utrecht; Willibald, his biographer; St Lioba, St Walburge, St Thecla.
He insisted on baptizing children by trine immersion, and refused the Communion to a pious German because he had not been baptized by a minister who had been episcopally ordained.
In the words of Hilary again: " Faithful souls would be contented with the word of God which bids us: ` Go teach all nations, baptizing them in the name of the Father and of the Son and of the Holy Ghost.'
In the age of the Council of Nice the custom arose of baptizing children of three, because at that age they can already talk and utter the baptismal vows and responses.