Francisco de Zurbarán
St. John of the Cross
1656
Oil on canvas, 100 x 77 cm. (39.3x30 in.)
Archdiocesan Museum, Katowice, Poland
The artist has combined all the features common in portraits of St. John of the Cross: the white mantle and dark brown tunic and scapular worn by Discalced Carmelites, and the crucifix and skull that refer to this saint's name and status as a contemplative.
The words in the upper right date the painting as August 21, 1656.
Read more about images of St. John of the Cross.
Source: Katowice Archdiocesan Museum via this page at Wikimedia Commons.