During the 16th century, strong economic development took place in Laredo, leading both to the renovation of the port in order to adapt it to trading relationships with Europe and America, and of the village, with the arrival of Renaissance lay and religious architecture.

As a symbol of the important role of the civil power in Laredo, the Town Halls were built in the 16th century, being located in the very centre of trading activity, alongside the docks.

Also during the Renaissance, the Franciscan monks left their monastery of Barrieta and settled in El Arrabal, building the classicist Convent of San Francisco. Inside the church, there is a magnificent 17th century altarpiece dedicated to San Francisco and many private chapels founded by powerful noble families from Laredo such as Marroquines, Alvarado, Salazar, etc.. These chapels have a rich décor, in some cases with valuable altarpieces, one of which keeps the praying statue of Don Felipe Vélez Cachupín. At present, the convent is occupied by the Trinitarian Nuns and some rooms of the building have been equipped as a museum of religious art.

The noble families of Laredo, who had prompted the building of private chapels in the convent of San Francisco and the renovation of the church of Nuestra Señora de la Asunción, left their imprint also on both Reinassance and Baroque private lay architecture. These buildings generally have the features of casonas and palaces montañeses. Some from the 16th century remain at present, such as the House of Villota, which had been occupied by the Franciscan monks until their convent was built, and the house inhabited by the corregidor of the League of the Four Villages of the Coast, known as the House of the Condestable. Moreover, the 17th century House of Mar, the 18th century House of Zaráuz and the House of Diego Cacho exist at present, all of them presenting on their façades the rich coat of arms of these families.

The superiority achieved by Laredo since the 16th century as the territorial authority of the League of the Four Villages of the Coast, had raised from that moment the wish to obtain officially the title of capital of that territory. In the second half of the 18th century, a campaign to obtain the desired title had been already initiated, and this ended up in the selfdenomination of the capital of the Bastón of Laredo.