Luca della Robbia, Madonna and Child with Saints
Church of St. Dominic, Urbino, Italy
The Madonna and Child are flanked by four saints in the habit of the Dominican order. The lily held by the saint on the left should identify him as St. Dominic. Next to him with the open book is St. Thomas Aquinas. On the far right the saint is probably Albertus Magnus, who is sometimes pictured with a quill pen in his hand. On his right is a saint whom one website has identified as Peter Martyr (Peter of Verona) but who does not have any attributes in this image.
The text in Aquinas's hand reads DE FRUCTU OPERUM TUORUM SATIABITUR TERRA, "The earth shall be filled with the fruit of thy works." This phrase from Psalm 103:13 is quoted in the Communion verse for the 12th Sunday after Pentecost in the Tridentine Missal (335). It may be relevant that Aquinas quoted it in his defense of religious mendicancy (Apology for the Religious Orders, II, iv, 12).
The Christ Child's scroll reads EGO SUM LUX MUNDI, "I am the light of the world." As is common in the 15th century, he is naked and his genitalia are in evidence.
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More of the Madonna and Child
More of St. Dominic
More of St. Thomas Aquinas
More of St. Peter Martyr
Source: Photographed at the church by Richard Stracke, shared under Attribution-NonCommercial-ShareAlike license.