Final answer:
Marqués de Rubí was assigned by Spanish King Charles III to inspect the missions and presidios in the frontier provinces of New Spain. This role held significance as Spain endeavored to improve governance in its colonies amidst rising independence movements across the Americas.
Step-by-step explanation:
The question pertains to a historical figure, Marqués de Rubí, and his assignment under Spanish King Charles III. Specifically, King Charles III assigned Marqués de Rubí to inspect the missions and presidios in the frontier provinces of New Spain. This task was part of Spain’s efforts to maintain and improve its colonial administration during a time when Spain was facing crises both in Europe, with the occupation by Napoléon, and in their American colonies, due to the rising tide of independence movements inspired by revolutionary ideas and the dysfunction of Spanish governance.
Marqués de Rubí's inspection was significant as it was done during the time when Spain aimed to consolidate and better manage its possessions in the Americas, following the similar administrative pattern it had been applying since the time of the conquistadors like Hernán Cortés. It was a period marked by shifting power dynamics and the initial stirrings of what would eventually become the widespread Mexican War of Independence.