The city of Bilbao was officially established in 1300 by Don Diego López de Haro, who was the lord of Biscay at the time. The decision to found the city stemmed from the need to develop a significant port that could harness the burgeoning trade opportunities in the region. Its location along the Nervión River made it a prime spot for maritime activities, offering easy access to the Bay of Biscay and facilitating international trade. Haro's vision was not only to bolster trade but also to enhance the local economy through urban development. As the city began to take shape, a market was established, and soon bustling streets were filled with merchants and tradespeople eager to capitalize on the new economic environment.

Bilbao's early days were characterized by rapid growth and the establishment of various commercial activities. The city's charter granted it privileges that encouraged settlement and economic development. These privileges attracted a diverse range of people, leading to a vibrant community and fostering a unique cultural identity. The significance of the port also drew attention from surrounding regions, further enhancing Bilbao's status as a crucial hub in northern Spain.

Over the years, Bilbao grew in size and influence, incorporating various populations and evolving into a key player in the economic landscape of the Basque Country. The foundation of the city set the stage for its later development into an industrial and cultural center, a trajectory that would heavily influence the history and development of the region.