|Saint Thomas, Apostle
In portraits St. Thomas often holds a book as a sign of his apostolate. His primary attribute is most often a carpenter's square (as at left) or T-square (example). This refers to the first episode of the Acts of the Holy Apostle Thomas, where the apostles draw lots to see who will bring the gospel to what countries. When St. Thomas draws India, he is reluctant to accept this difficult mission, but Jesus settles the issue by selling him to a royal official just arrived from India looking for a slave skilled in carpentry. In the Golden Legend, the official is seeking an architect; in Caxton's translation, a mason.
At times the primary attribute is not a square but a spear (example), which refers to manner of St. Thomas's death in earlier hagiographies such as the Consummation of Thomas. (In the Golden Legend, he is killed with a sword -- a "glaive" in Caxton -- which would be problematic as an attribute because of its association with St. Paul.)
Both the square and the spear seem to have lacked the currency of other apostles' attributes. In an array of sculptures of the apostles in Parma's Duomo, St. Thomas has to hold up a scroll that says "Thomas," even though Bartholomew standing beside him is given only his customary book and flaying knife.
The most common narrative image of St. Thomas involves his placing his fingers into the wound in Christ's side (example), as recounted in John 20:24-29 (cached). In some instances, Christ's hand guides St. Thomas's into the wound (example).
In some texts relating to the Assumption of the Virgin, St. Thomas arrives late and either demands proof of the Assumption or attests to it (having seen it from afar) and is asked for proof by the apostles. In either case, the proof is Mary's belt (example).
Feast day: December 21
At left, "St. Thomas" - St. Mary's Cathedral, Pamplona
Caravaggio's "Doubting Thomas"Also see:
Golden Legend #5: html or pdf
Acts of the Holy Apostle Thomas (cached)
The Consummation of Thomas (cached)