The Royal Arch degree is not native to Scotland, but seems to have been introduced from both Irish and English sources, often Military Lodges, towards the middle of the eighteenth century. The earliest reference to the degree is at Stirling in 1743.
These Military Lodges introduced many other degrees beyond the Craft, and when the regiments moved on, Lodges in the vicinity sometimes continued to work them. This situation continued until the end of the eighteenth century.
However, the early Secret Societies Acts caused the Grand Lodge of Scotland, in 1800, to issue a warning to its Lodges against the working of any degrees other than those of Entered Apprentice, Fellow Craft and Master Mason.