... The first Erasmus was tortured to death in Diocletian's persecution, at Formici, whence his relics were transferred to Gaeta, and he there became the patron of the Mediterranean sailors, who used to invoke him as St. Ermo or St. Elmo, at the approach of a storm, and he thus was thought to send the pale pure electric light that shimmers on the topmast, warning the sailor of the impending storm.  The name of Erasmus was assumed by the learned Dutchman, under the belief that it translated his name of Gerhard (really spearhard), and from him Rasmus and Asmus are common in Holland, and Rasl has somehow found its way to Bavaria... (History of Christian Names, Yonge, 1884)