In celebrating St. Patrick's Day on Saturday, the Duchess of Cambridge was in good spirit while visiting the Irish Guards. This marks her first solo military engagement since marrying Prince William. 　　Sporting a dark green Emilia Wickstead dress and with a gold shamrock-shaped brooch that was previously worn by the Queen Mother, Prince William's great-grandmother, who died ten years ago, the Duchess posed for a group photo with the 1st Battalion Irish Guards at the ceremony. 　　She also handed out sprigs of shamrock to the soldiers in the Royal tradition, which dates back to early 1900s, when it was first started by Queen Alexandra.