(An), in Christian art. St. Stephen (the Pope), and Thomas Becket are represented as immolated before an altar. St. Canute is represented as lying before an altar. St. Charles Borromeo is represented as kneeling before an altar. St. Gregory (the Pope) is represented as offering sacrifice before an altar. And the attribute of Victor is an altar overthrown, in allusion to his throwing down a Roman altar in the presence of the Emperor Maximian.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894