Owain Glyndŵr, a Welsh nobleman, declared himself Prince of Wales in 1400, initiating a significant uprising against English domination in Wales. By 1404, he sought external assistance to further his campaign against King Henry IV of England. In a strategic move, Glyndŵr allied with the French, who were also interested in weakening English power on the continent. This alliance was formalized as Glyndŵr aimed to secure military support, both to bolster his forces and to gain legitimacy for his rule among Welsh supporters. This partnership enabled the Welsh rebels to stage stronger offenses against English forces, particularly in the context of the ongoing conflicts in England's territories, where the French were eager to exploit England’s vulnerabilities during the Hundred Years' War. A notable aspect of this alliance was a diplomatic effort that led to promises of military assistance from the French, which would prove essential for the Welsh uprising against English authority. The commitment to collaboration underscored the shared interests in destabilizing King Henry IV’s regime and highlighted the ongoing struggle for Welsh national identity.