A Bronze Age shield found in a peat bog has been returned to Scotland for the first time in more than 230 years. The "spectacular and intricate" combat guard was discovered during labouring work in a field in Beith, North Ayrshire, in about 1779 and was presented to the Society of Antiquaries of London in 1791 where it has remained since. It has now been loaned to the National Museum of Scotland (NMS) for the first time as part of an exhibition entitled "Scotland's First Warriors," which is due to open this summer. The shield will join five others from the time period in the exhibition, which experts have described as a "once-in-a-lifetime" opportunity. The Bronze Age in Scotland spans a 1,400-year period from about 2,200 BC to about 800 BC. It covers the early production of bronze – a copper and tin alloy – up to the first uses of iron. The shield, which measures about 60-70cm (23-27in) in diameter, is decorated with hammered bosses and ribs.…