The establishment of Oulu in 1605 was a significant milestone in the historical development of northern Finland. Charles IX of Sweden aimed to fortify Swedish influence in the region, which had strategic importance due to its proximity to both the trade routes of the Baltic Sea and the interior lands of Finland. By founding Oulu, he created a urban settlement that would serve not only as a trading hub but also as a military base for Sweden's northern campaign. The location along the Oulu River enabled ease of transportation and access to resources, pivotal for economic sustainability.

The newly founded city faced several challenges initially, including the integration of various local populations and the need to establish trade networks. Oulu attracted settlers, merchants, and craftsmen, all essential for developing a vibrant community. The blending of cultures, particularly as Sámi people interacted with Finnish and Swedish settlers, contributed to the area's unique identity over the years. Oulu's initial growth laid the groundwork for its evolution into a central figure in Finland's economic and cultural landscape.

The foundation of Oulu also represented Swedish ambitions in establishing a foothold in the northern territories, part of a larger trend during this period where European powers sought to expand their territorial claims and economic influence. By developing Oulu, Charles IX reinforced Sweden's presence in the region and launched a new chapter in its northern affairs, with effects that would resonate for generations.