During the era of the American Revolution, muster rolls were prepared for each six-month period for each company of a regiment. A single roll is a sheet that gives the name and rank of each officer, serjeant, corporal, drummer and private soldier in the company during that six-month period. If a man was not in the company for the entire period, then an annotation gives the date and the event that caused the change: "joined", "enlisted", "entertained", "landed", "from" another company or what have you if he came into the company; or "discharged", "died", "deserted", "to" another company or what have you if he left.
At least, that is the ideal case, and it is generally true for most regiments for most of the war years. But sometimes dates are missing, and sometimes an entire annotation is missing such that men appear for the first time with no date or reason given - or disappear. Sometimes the missing information can be deduced from other sources, sometimes not.
The muster rolls were prepared after the end of the period they described - usually within a month or two, but sometimes not for a few years. This was particularly true when regiments were captured or became very busy with intense campaigning; in some cases, the rolls for an extended period were all prepared at once, in other cases they weren't prepared at all leaving us with gaps in the records.
The purpose of the rolls was financial; each regiment was provided with sums of money to pay its soldiers, and the muster rolls were an ex post facto way of representing where the money went. As such, the dates are deceptive. The date on which a man "enlisted" was the date on which he began drawing pay through the specific company, often months or years after he actually joined the army with a recruiting party, but sometimes when he embarked on a transport before actually joining his regiment in America. When a man was discharged he usually received a few weeks' extra pay to provide for his journey home; the muster rolls give the date through which the man was paid rather than the date on which he actually left the regiment. All of this becomes clear only because, for some men, other information exists that provides actual dates and clarifies the administrative dates given in the rolls.
The geographic distribution of the army also caused nuances in the rolls. A case in point is John Overon, a five-foot-six-inch tall laborer from Balking, Essex who enlisted in the 34th Regiment of Foot in 1769 at the age of 18. He does not appear on the 34th's muster rolls until the second half of 1771. His career can then be easily traced (allowing for variations in the spelling of his name such as "Overhead") through service in Ireland and deployment to America in 1776. The 34th Regiment was sent to Canada and Overon served there for most of the war. In the first half of 1782, in circumstances that we have not yet learned, he was captured; the muster roll for that period denotes him as “Prisoner with the rebels”.
When the war ended, prisoners of war were repatriated. Some did not return, having either died in captivity, escaped and disappeared into the coutryside, or chosen to stay behind after their release. The British army gave a directive that these men be listed on the muster rolls as having "deserted" in June 1783, an arbitrary way to adminstratively write them off. Overon and some other prisoners were not even given this much attention; they simply no longer appear on the rolls. For a researcher attempting to study an individual soldier, this leaves a dead end. The only assumption is that the man had died or chosen to resettle in the colonies.
But that's not what happened to John Overon. He escaped from captivity and made his way not to Canada but to New York. Rather than send him back to Canada, he was drafted into the 22nd Regiment of Foot on 1 January 1782 (another date that sounds suspiciously administrative). He continued to serve in that regiment for another ten years, taking his discharge in Dublin in July 1791 at the age of 40 after 22 years as a soldier, “being affected with a beginning consumption and otherwise infirm and Old.”
The muster rolls of the 22nd Regiment record him simply as having "enlisted" with no indication that he was in fact an experienced soldier from another regiment. The only reason we know he came from the 34th Regiment is because his discharge paper from the 22nd Regiment survives. It gives the number of years he served in each of the two regiments, which correlates perfectly with the muster rolls. Had he not received a pension, this document would not exist and we would have no way of connecting the names on the muster rolls of regiments that were posted so far from each other. There are other men for whom the muster rolls do not tell the complete story, and probably many more with interesting careers that cannot yet be deciphered.
