The role of port became inscribed very early in the history of the town of Bayonne.

In the Middle Ages, Bayonne truly became a sea and river port that experienced its golden age in the 12th to 14th centuries, during the time of the English suzerainty.
Established at the confluence of the river Adour and its tributary, the Nive, the area called "la grand mar", the village spread its port activities over both banks of the Nive. 

Moreover, reached by the "barthes" or water plains, the lower town was an area of inner "ports", that is tidal canals navigated by small boats such as the locally named "tilholes" and "galupes".

The port's reputation lay to a greater extent in its shipyards that built vessels for the high seas (ships, galleys, pinnaces, 8-oared boats, etc.) 
Trading relations with Navarre, Flanders, the Hanseatic towns and more especially with England were prosperous.

To further this activity that was essential to the town, the Bayonne townspeople continually struggled to master the river and its opening into the Atlantic ocean.
During the Middle Ages, the Adour reached the sea at Capbreton, an earlier port situated some fifteen kilometres from Bayonne.

Towards 1410-1430, natural phenomenon led to the river mouth being further north, 32km from the town, leading to the decline of maritime activities.

In 1578 a colossal feat of engineering led by master engineer Louis de Foix created an artificial opening 6km from the city. This new river mouth in Boucau improved the town and the surrounding countryside.


 

The ship is a vessel of the high seas with a single mast, clinker planking and an axial rudder (also called a sternpost rudder) "à la bayonnaise" or "à la navarresque" Sculpture of the key to the vault in the south transept wing of Bayonne cathedral (photo association Lauburu)	Map glued on canvas, drawn in ink and watercolours dating from 1840 (archives CCI Bayonne)
Extract from the 1840 map presenting the river mouth at Capbreton in the Middle Ages (until 1410-1430) Bayonne was 15km from the Atlantic Ocean by river.	Extract for the 1840 map presenting the river mouth at Vieux-Boucau from 1410-1430 to 1578 : Bayonne was thirty or so kilometres from the Atlantic Ocean by river.
Extract from the 1840 map presenting the river mouth created by the engineering works of Louis de Foix (before the works)	Part taken from the map. At this time Bayonne is 6 kilometres from the Ocean (after the works)