What other name was Saint Patrick called?

Patrick's birth name was Maewyn Succat but his name was changed by Pope Celestine I before he was sent to Ireland as a bishop and missionary.

St Patrick (Padraig) was certainly called by his real name. Unfortunately, that name has been lost to history. Patrick is a nickname, from the Latin "Patricius" (patrician or nobleman). That could have been from his high regard by the people who nicknamed him, from their inability to pronounce his real name; or out of irony in that he had once been a slave in Ireland, escaped, and returned later to bring the Gospel, literacy, and abolition of slavery.