Here’s a bit of a change: Karwansaray Press publishes Ancient Warfare magazine, which is open to non-fiction essays on that very topic:
Articles are written for a large audience, interested in ancient military history. This means that the article should be both informative and based on modern academic research, but written in a smooth and easily accessible style.
Be original. Captivate the reader with an interesting narrative. The course of battles, developments in wars, strategies and weaponry is more attractive than a digression on literary sources or a detailed account of a scientific debate (except when the topic of your suggested article is a particular debate).
They accept pitches for articles, and are paying 10 euro cents per word for essays between roughly 2,000-4,000 words.
Literarium listing here: https://literarium.net/market/karwansaray-publishers/ancient-warfare/1