This Christian scene marks the martyrdom of Christian soldiers on Mount Ararat (modern day Turkey) by the Persian King, Shapur I. You will find the King on the right hand side of the composition, riding a horse. This would help to give the impression of his power over the others in the scene. This method was also used by Rubens, Velazquez and many others in the Renaissance and Baroque periods.
Amongst the carnage found in this painting there are two figures standing isolated in the middle of the painting. These are believed to be the artist himself and a close friend, Conrad Celtes. The idea of placing yourself into a painting as a background feature was also used by Diego Velazquez in Las Meninas.
You can find the original painting at the Kunsthistorisches Museum in Vienna, alongside another impressive Albrecht Durer painting of Adoration of the Trinity. This was originally a panel painting before being transferred to canvas which was a common restoration technique in previous centuries. In the modern era there are now better ways of protecting wood-based canvases.
One common choice for Durer was to cover the same themes within different mediums, with his skills being spread between painting, drawing, engraving and woodcuts. In this example there was a similar woodcut from 1496, which perhaps was an inspiration for this later painting.
Durer made several significant changes to the tone of the painting, removing elements of the woodcut which were considered inappropriate for the position in which the painting would be displayed.
It is the vicious treatment of one particular bishop which was deemed unsuitable for the All Saints' Church in Wittenberg. This is just one of a number of high profile amendments which were necessary prior to installing Renaissance art, see also the changes made by Michelangelo in The Last Judgement.