What was the first country to celebrate Saint Patrick's Day?

St. Patrick's Day originated as the feast of Saint Patrick. That means that after his death around 461 the Catholic Church honored the missionary to Ireland as a holy person by celebrating his date of death (or presumed date of death) with liturgical prayers. Since he worked and died in Ireland, the feast began there, then spread to other countries. In modern times it is celebrated like a holiday even in countries where Irish people emigrated. While the actual date of death is unknown, Patrick was venerated on March 17 in the sixth century in Ireland and in the seventh century in what is now France and other parts of Western Europe.