The Crucifixion of Saint Andrew is a painting by Caravaggio in the tradition of the veneration of saints common to Catholicism and Christian Orthodoxy.

"Worship," like "cult," can be an ambiguous word, so Catholic and Orthodox adherents use two Greek words to describe the distinction between the forms of honor for saint, and for tributes to the Holy Trinity. The Trinity's worship is latria, and is less ritualistic, while proskynesis is dedicated to angels, relics, icons, and figures like Saint Andrew. Andrew's name was Andreas, meaning "manhood" or "honor" in Greek, which is unusual, because Christian tradition holds that he was the brother of the apostle Peter, whose Hebrew name (Simeon) is well attested, but Andreas seems not to have had a Hebrew name at all. The armored man in this painting is Egeas, proconsul of the Roman empire, who makes a cameo in another Caravaggio painting maintained by the Kunsthistorisches Museum Vienna.

As you can see in the lower portion of this work, Caravaggio follows a storytelling tradition that developed in medieval Europe, showing Andreas's cross in a different shape, that of an X, which they call the crux decussata. This version is so popular that it is the form of the national flag of Scotland. The story of Andreas, as recorded in the Acts of Andrew, is apocryphal, meaning that church authorities, for the last 1,800 years or so, consider it about as authoritative as college professors consider TMZ. For some set of reasons, church patriarchs voted it off the island within a few hundred years. This redaction didn't laminate the stories into one version, as the patriarchs hoped, but seems to have done the opposite. For instance, the early Acts of Andrew attested by Gallo-Roman historian Gregory of Tours describes Andreas bound to a cross, as Caravaggio shows, but claims that it was a typical Latin cross, of the form that appears in churches, not a crux decussata. 

There are three existing copies of this work, two of which are by Caravaggio's hand. This painting was once owned by Juan Alonso Pimentel de Herrera, Viceroy of Naples, a Knight of the Order of Santiago, Grandee of Spain, 5th Duke of Benavente.