Not an easy questions to answer. However, I will say that the memorialization of soldiers and various battles have numerous "war memorials" throughout history. Ancient cultures going back to the early Mesopotamian cultures built memorials to depict military victories. Looking at a list of Roman holidays and feasts one could argue that a number of them would venerate soldiers and veterans. Most significantly I would look at Armilustrium (October 19th) and Equirria (March 14), when the army would be blessed . There is also Lucaria (July 19, 21), a festival that commemorated the defeat of the Gauls.