The Sappers or Royal Engineers (formerly Sappers & Miners) can trace their roots back to 1066
Sapper has two meanings, a term for any Royal Engineer regardless of rank and the equivalent of Private soldier in the RE.
The number of jobs or trades in the RE at the time covers many aspects. The RE ran the Army Postal Services, the Army railways, the ports, Combat Engineering (including bridge building) & Airfield construction. All mapping was the responsibility of the Sappers (I was a surveyor in the RE myself), there were carpenters, electricians, saw doctors the list goes and on. Not least there was & is EOD, commonly known as bomb disposal. Alas many of the trades have moved from the RE, first to the Royal Corps of Transport and on its demise to the RLC. There are airborne units of the RE.
The RE Museum is your best reference.
www.remuseum.org.uk/ The current trades in the RE can be seen here
http://www.army.mod.uk/royalengineers/careers/trades/index.htmIt may be of interest that the following had a least part of their origins in the Royal Engineers
Royal Air Force
Royal Signals
Royal Electrical and Mechanical Engineers (REME)
Royal Logistics Corps (via Royal Corps of Transport)