But Philip Freeman , author of the biography `` St. Patrick of Ireland , '' says while it is almost certain that Patrick 's family owned slaves , as many members of the Roman nobility did at the time , experts ' claims that Patrick himself was a slave trader is reading too far into the sources . St. Patrick 's Day is the feast day St. Patrick , patron saint of Ireland . Study : Patrick may have sold slaves in order to pay his way to Ireland to avoid tax collector job in Britain . Comment: Legend : Patrick used shamrock , national emblem of Ireland , to explain concept of Holy Trinity .
St. Patrick 's Day is the feast day St. Patrick , patron saint of Ireland . Study : Patrick may have sold slaves in order to pay his way to Ireland to avoid tax collector job in Britain . Comment: Legend : Patrick used shamrock , national emblem of Ireland , to explain concept of Holy Trinity .