Durand Robert (2004) “L’or musulman et la formation du Royaume du Portugal” in Michaud Françoise (ed.) Les Relations des pays d’Islam avec le monde latin du milieu du Xe siècle au milieu du XIIIe siècle, Paris, Vuibert, 250-261.
In the early 20th century, M. Lombard proposed the following thesis: the Muslim expansion triggered a major de-hoarding movement of the Sassanid and Byzantine gold reserve held in the newly conquered territories. According to R. Durand, a rather similar event may have followed the Almoravid and Almohad conquests of Spain. And it may have had a significant impact upon the formation of the Portuguese kingdom (p.250).
A cash drought
During the Taifa period (1031-1086) gold nearly disappeared from what is nowadays Portugal. Less than 2% of prices were expressed in monetary terms: exchange in kind prevailed (p.251). The modio (volume of cereals) and the bragal (piece of cloth) were used as money of account (p.252).
The Almoravid conquest (1086) coincided with the reappearance of prices expressed in monetary terms (38% in Portugal were expressed in gold dinars or maravedis). Yet the reasons for this renewed flow of cash and its relationship with the Almoravids remain unclear (p.253). The Coimbra region was the quickest to adopt the maravedis for major transactions around 1120. On the other hand in the Northern regions the shift took place only around 1160 (p.254).
It could be argued that the actual maravedis were a mere money of account and that golden coins were seldom used; silver currencies were more flexible and barter could have remained widespread (p.255). But the re-appearance of gold coins was very real, the Christian raids in Muslim lands and the parias (sums paid by Muslim emirs to their Christian protectors) brought several tons of gold to the Catholic states. It allowed the appearance of a monetarized economy to grow (p.256). This gold fuelled a noticeable economic development through the importation of precious goods from Al-Andalus and Northern Europe, the construction of major buildings (mostly churches and convents) and the purchase of land. It allowed the creation of a merchant class in Portugal (p.257).
Of gold and kings
In the hands of the Portuguese kings this gold enabled the monarchs to create a centralized royal administration made of civil servants rather than feudal lords. A luxury unknown to European rulers outside Iberia. For example, Dom Afonso Henriques (1143-1189) was able to stop giving away fiefdoms to his soldiers as early as 1150 (p.258). Significantly the Northern regions which were the least irrigated by Muslim gold were also those where the feudal system was the strongest. Thanks to this unique fiscal might the Portuguese king could pay his troops rather than relaying on feudal levies (p.259).
Symptomatically Dom Afonso Henriques choose Coimbra as capital city in 1131, despite the fact that the town had little other advantages than being the main point of entry of Muslim gold in Portugal. It is also very likely that this same gold allowed Portugal to become the first European country to enjoy a modern constitution with the ordinances of Afonso II in 1211 (p.261).