In 1269, the French scholar Petrus Peregrinus de Maricourt wrote "Epistola de Magnete" while serving as a military engineer at the siege of Lucera in southern Italy. This letter, addressed to a friend, described experiments with lodestones and introduced the concept of magnetic poles for the first time. Though primarily about magnetism rather than electricity, the work established the experimental method that would later prove essential to electrical science.

Peregrinus's letter is a landmark in the development of scientific writing in the vernacular tradition, bridging the gap between medieval scholastic Latin and the more accessible prose that would emerge during the Renaissance. Its epistolary form influenced later natural philosophers who wrote about electrical phenomena in letters and informal treatises, a format that shaped the intimate, conversational tone found in much Romantic-era literary prose.