Martirio de San Acacio (Martyrdom of St. Acacius)
Toledo, 16th century
Oil on panel, 43.7 x 25.6 in. (111 x 65 cm.)
Museo del Prado, Madrid, Spain
According to the commentary on this painting provided at the Prado's website, the story of this St. Acacius is told in the Passio decem millium martyrum. The saint was crucified on Mount Ararat in the 2nd century with 10,000 fellow soldiers who had converted to Christianity, even though they had just given the Emperor an astonishing military victory.
This is not the St. Acacius who was beheaded at Byzantium under Diocletian, nor the Bishop Acacius who was one of the "14 Holy Helpers."
Source: Wikimedia Commons