The primitive mosque of Abderraman I (785) was made up of eleven naves set out lengthways from north to south. The most striking feature in this part is how Roman or Visigothic columns and capitals were reused, set at differing heights to adjust to the straight lines of arches above them, rather than being lined up at floor level. Another surprising feature is that this first Mosque, as well as all the future extensions, was built facing south, just like the Mosque of Damascus.
Several possible explanations have been given for this fact, but the most likely explanation is that the sandy ground around the River Guadalquivir made it impossible to build the Mosque facing Mecca, in the orthodox way. The main focal point inside the Mosque is the prayer niche.
The use of horseshoe arches was borrowed initially from Visigothic art, but it later went on to become a trademark of Islamic architecture. The rows of arches dividing each nave are on two levels: on the lower level, a horseshoe arch, and above that, a semi-circular arch. The alternating stone and brick work gave the Mosque its characteristic two-tone appearance, and set a model for future Islamic buildings. The arches on two levels meant that the ceiling was higher and the interior was better lit, and the idea may well have been taken from the Roman aqueduct of Los Milagros (Mérida).
Abderraman I was followed by his son Hixem I, who built the first minaret for the Mosque, and was also responsible for the galleries built around the courtyard, where the women were allowed to pray, as well as the first ablutions font. This was how the first, and principal, Mosque in Cordoba started off. In the following years, as the Moslem population increased, so did the rulers' desire for grandeur, and the Mosque was enlarged on several occasions until it reached the size which we know today.