My daughter recently went on holiday to Eastern Europe. One of her photos is through what looks like an arrowslit widened for primitive gunpowder weapons. Were they still called arrowslits or did they then change name?
Judging by usage on this page (http://www.castlesandmanorhouses.com/architecture_03_walls.htm), they became embrasures.
Using their alternative name of arrow-loop, they evolved into gun-loops.
Thank you. Very useful.