Monarch's model A was the first lathe they built in 1909 in either 14" or 16" swing. They produced this lathe till about 1930 when it was replaced with the AA. They built it with either a cone headstock or a spur geared headstock. There is a general parts book. Monarch made several thousands of these lathes during WW1, and odds are it is from this period.
Question, does your machine have a quick change gear box? The earliest of these lathes did not have this, and the Quick change box was an option for many years.
If you have any specific quesitions, please ask and I will try to see if I can find an answer.
John