Master James of St. Georges – or more formally Jacques de Saint-Georges d’Espéranche – was a Savoyard employed by England’s Edward I to design and build castles to keep his new but unruly subjects in line. Edward Longshanks kept grabbing chunks of Wales from 1277 to 1283 AD, when Llywelyn ap Gruffudd was finally killed in battle at Orewin Bridge. Concerned about a rebellion among the Welsh lords while he turned his attention north to the Scots, the king ordered the building of castles. Edward likely had met James – son of a master mason working in Savoy – in 1273 on a state visit, and hired him as his 'ingeniator' (chief engineer) in 1278.

James got busy building castles for Longshank’s Welsh occupation; at least 12 of the 17 English castles built in Wales during this period are his work. At Rhuddlan, James’ first effort, he perfected the symmetrical, concentric “walls-within-walls” which became his trademark. His castles soon dotted the Welsh countryside – Conwy, Flint, Harlech, Caernarfon, and Beaumaris among others. Around September 1298 James joined Edward in Scotland to set about intimidating another bunch of savages with his castles, but managed to expand the fortifications at only Linlithgow Palace and at Stirling before his death in 1308.