In various fantasy works, you often have “lancers” as one of the primary types of troops. I’m not aware of any time in history when lancers were that prominent, although I am certainly not familiar with every era of history. Is there a reason, possibly related to how you picture the various magic systems impacting war, for the use of lancers so commonly?
The magic system was certainly the reason for the use of Mirror Lancers in the Recluce books, because in the time of Cyador, firelances were a stand-off weapon. Another factor is that the population density, especially in Candar, is comparatively low and the distances between communities, except along the Great Canal, mitigate against infantry… and there’s a lot of grassland.
In the Corean Chronicles, rifles and magic were both stand-off weapons, but magic definitely precludes large massed armies. In the Imager Portfolio, the fighting forces in the early years were more like mounted infantry.
Historically, there have definitely been notable eras where the predominant military force was mounted, but such forces work better in areas of lower population density, and where forage is abundant, similar to the lands I’ve created.
But I suppose part of the reason is that, as a former Naval officer and pilot, I prefer not to deal with the grinding brutality of soldiers on foot making mincemeat out of each other, and I’ve created worlds where it’s not quite as necessary or workable.