Description:The Duke and Duchess of Cambridge took part in traditional St Patrick's day celebrations with Irish guards in England on Sunday (March 17). Prince William's pregnant wife Catherine, popularly known as Kate, presented members of the 1st Battalion Irish Guards with sprigs of shamrock in a tradition dating back to 1901 when it was started by Queen Alexandra. The Duchess also honored the regimental mascot, an Irish wolfhound, by pinning a shamrock to its collar.(0:34)