The entire mainlands of both Gaul and Hispania were possessions of the Roman Empire.

While the term "Spain" may be improper when used to refer to France–Spain relations before the union of the Crown of Castile and the Crown of Aragon in 1476, there has always been important relations between what are now France and Spain.

One important feature of those early relations was that counts from the Marca Hispanica & Navarre fought shoulder to shoulder with Frankish Kings (during the Carolingian dynasty), to protect Europe from the Al Andalus Muslim kingdom.
Barcelona was a County of the Frankish Empire, under protection of the Franc Imperator.


This vassality of Marca Hispanica and Navarre to the Frankish empire remained effective up to 985.
At that point, because his armies were mobilized in the Verdum's county, Lothair of France and his Byzantine allies did not assist Navarre & Marca Hispanica in its defense against the Caliph, implying that they failed to defend Barcelona from the Arabs.
Almanzor did not stay in the cities (the first assault was launched July 6, 985; withdrew their troops July 23), but this incursion was arguably the first step of a process of independence of the county of Barcelona from the kingdom of France, and heralded what would become the Aragon kingdom.
While independent of France and integrated in the Crown of Aragon, Barcelona remained legally a county of France and the King of France retained a  de jure right to vote in the Barcelone Courts in the next centuries.
This situation generated numerous territorial conflicts between the two kingdoms to control what is now the south of France and the north of Spain (the support of Aragon to the Count of Toulouse, death in Perpignan of Philip III of France married to Isabel of Aragon, and Albigenses Crusades are some of the most famous examples) and played a significant political role in the start of the Catalan Revolt which ended with the treaty of Pyrenees.
The entire mainlands of both Gaul and Hispania were possessions of the Roman Empire.
While the term "Spain" may be improper when used to refer to France–Spain relations before the union of the Crown of Castile and the Crown of Aragon in 1476, there has always been important relations between what are now France and Spain.
One important feature of those early relations was that counts from the Marca Hispanica & Navarre fought shoulder to shoulder with Frankish Kings (during the Carolingian dynasty), to protect Europe from the Al Andalus Muslim kingdom. Barcelona was a County of the Frankish Empire, under protection of the Franc Imperator.

This vassality of Marca Hispanica and Navarre to the Frankish empire remained effective up to 985. At that point, because his armies were mobilized in the Verdum's county, Lothair of France and his Byzantine allies did not assist Navarre & Marca Hispanica in its defense against the Caliph, implying that they failed to defend Barcelona from the Arabs. Almanzor did not stay in the cities (the first assault was launched July 6, 985; withdrew their troops July 23), but this incursion was arguably the first step of a process of independence of the county of Barcelona from the kingdom of France, and heralded what would become the Aragon kingdom. While independent of France and integrated in the Crown of Aragon, Barcelona remained legally a county of France and the King of France retained a  de jure right to vote in the Barcelone Courts in the next centuries. This situation generated numerous territorial conflicts between the two kingdoms to control what is now the south of France and the north of Spain (the support of Aragon to the Count of Toulouse, death in Perpignan of Philip III of France married to Isabel of Aragon, and Albigenses Crusades are some of the most famous examples) and played a significant political role in the start of the Catalan Revolt which ended with the treaty of Pyrenees.
France–Spain relations