During the early 15th century, Portuguese expansion efforts focused on North Africa, particularly Morocco, as part of their ambitions in maritime exploration and trade. In September 1437, a Portuguese expeditionary army, led by Afonso I, aimed to seize the Moroccan city of Tangier, known for its strategic location controlling access to the Mediterranean. The expedition was motivated by the desire to establish a foothold in the region and further Christian interests against Muslim territories. Initial plans included a small naval fleet landing troops who would then besiege the fortified citadel. Upon arrival, the expedition faced unexpected and fierce resistance from a well-prepared Moroccan garrison. Communication and logistics issues compounded the difficulties the Portuguese faced. As the siege progressed over several days, it became clear that capturing the citadel would come at a high cost in lives and resources. Finally, after suffering heavy casualties and recognizing the untenable position, Afonso ordered a retreat, which forced the remnants of his forces back to Portugal, marking the operation as a failed military endeavor.