Caught up in the maelstrom of battle between the Greeks and Trojans, these horses have just seen their master massacred, and free of his chariot, and possibly traumatised by the violence, they try to bolt, but are held back.
Homer never shies away from the graphic horror of war, as these horses shy away from it. He speaks of glory in war yet manages not to glorify it.
‘… and the Myrmidons close by held in the hard-breathing horses
as they tried to bolt away, once free of their master’s chariot.’
Source: Homer, The Iliad of Homer, trans. Richmond Lattimore (Chicago: Chicago UP, 1961 (1951)), book XVI, p. 344