Distemper on canvas, 67.3 x 30.7 in. (171 x 78 cm.)
Museo Nazionale di Capodimonte, Naples, Italy
St. Euphemia is identified by the lion at her side and the sword piercing her breast. According to the version of her passion authored by John the Stylite she was exposed to lions in the arena, but they simply licked her feet. In the Golden Legend the evil judge then has her stabbed in the breast with a sword, which ends her life.
In addition to these particularizing attributes Mantegna also pictures Euphemia holding a lily stalk and palm branch, symbols respectively of her virginity and her martyrdom.
Read more about images of St. Euphemia.
Source: this page at Wikimedia Commons.