Aquilonia is a Hyborian nation that reigns "Supreme in the dreaming west".
Aquilonia at WarEdit
"THE AQUILONIAN host was drawn up, long serried lines of pikemen and horsemen in gleaming steel, when a giant figure in black armor emerged from the royal pavilion, and as he swung up into the saddle of the black stallion held by four squires, a roar that shook the mountains went up from the host. They shook their blades and thundered forth their acclaim of their warrior king – knights in gold-chased armor, pikemen in mail coats and basinets, archers in their leather jerkins, with their longbows in their left hand." -The Hour of the Dragon
Aquilonia is a feudal kingdom. Like other Hyborian peoples they prize cavalry, but their practical focus has shifted towards the use of more professional heavy infantry and archers, especially from Gunderland and Bossonia. It is given in The Hour of the Dragon that Nemedia uses their infantry to "clear the way" so their knights can do the real work of battle. This does not appear to be the case with Aquilonia - though the heavy cavalry play an undoubtably important role, it is the infantry that does the heavy lifting of the army.
Aquilonia makes good use of bows, similar to Shem. It is likely that the Shemite archer is every bit as good as a Bossonian, though it is possible that the Bossonians have superior bows, while Shemite archers may be more heavily protected.