Final answer:
The Spanish March served as a frontier between the Frankish Empire and the Muslim territory of Al-Andalus. In the context of colonial expansion, the Treaty of Tordesillas in 1494 defined the division of new territories between Spain and Portugal, not the Spanish March.
Step-by-step explanation:
The Spanish March referred to the borderlands or buffer zones that the Frankish Empire (and later the Holy Roman Empire) established to separate themselves from the Islamic territories to the south, particularly Al-Andalus, the Muslim-ruled area of the Iberian Peninsula. This frontier region served as both a defensive barrier and a point of contact between Christian and Muslim territories in the early Middle Ages.
In the context of the Treaty of Tordesillas and the later division between Spanish and Portuguese colonial ambitions, the Spanish March discourse could be misspecified since these events pertain more to the division of newfound territories across the Atlantic. According to the Treaty of Tordesillas in 1494, the newly discovered lands to the west of an imaginary line drawn in the Atlantic Ocean would belong to Spain, while the lands to the east would belong to Portugal. As a result, Spain gained rights to the Americas and built its empire there, whereas Portugal claimed lands in Africa, Asia, and eventually Brazil, after renegotiating a more favorable line, almost 2,000 miles west of the Cape Verde islands.