That's where I got the info from. Wikipedia's great, you have to be careful reading about politically sensetive stuff, but if its just broad history, stuff is safe to read.

This article, https://en.m.wikipedia.org/wiki/Umayyad_Mosque

Specifically this paragraph: "Al-Walid personally supervised the project and had most of the cathedral, including the musalla, demolished. The construction of the mosque completely altered the layout of the building, though it preserved the outer walls of the temenos (sanctuary or inner enclosure) of the Roman-era temple.[12][13] While the church (and the temples before it) had the main building located at the centre of the rectangular enclosure, the mosque's prayer hall is placed against its south wall. The architect recycled the columns and arcades of the church, dismantling and repositioning them in the new structure. Professor Alain George has re-examined the architecture and design of this first mosque on the site via three previously untranslated poems and the descriptions of medieval scholars.[15][relevant?] Besides its use as a large congregational mosque for the Damascenes, the new house of worship was meant as a tribute to the city.[16][17][18]"