Saint Erasmus (303)

He was a bishop in Campania in Italy who was martyred after undergoing terrible torments. He is one of the fourteen Holy Helpers and is invoked against stomach ailments. He is also the patron of sailors, who call him Saint Elmo.

Saint_Erasmus's_altar_(Turing.,_15_c.)_detail_1

Saint Erasums Altar, 15th Century, photo by Shakko (source)

See also: The Fire of Saint Elmo.