The Dome of the Rock, begun in AD 688 and finished in 691, is the first major sanctuary built by Islam. It is also the only one to have survived essentially intact.
The extraordinary impression produced by this building is in part due to the mathematical rhythm of its proportions. All the critical dimensions are related to the centre circle circumscribing the rock. The plan has its closet parallel in the Mausoleum of Diocletian (AD 303) in Split, Croatia, but the same principles were used in the construction of Byzantine churches in Italy, Syria, and Palestine. In none of these, however, do we find the integration of plan and elevation that is evident here.
According to current Arab tradition, the purpose of the Umayyad caliph Abd al-Malik in building the Dome of the Rock was to commemorate Muhammad’s Ascension into heaven after his night journey to Jerusalem (Sura XVII), but were this in fact the case there would have been no need to erect the later Dome of the Ascension (Qubbat el-Miraj) nearby! Abd al-Malik’s purpose was more complex and subtle. By erecting a beautiful building he intended to instill a sense of pride in Muslims overawed by the majestic churches of Christendom, tours of which were organized by the clever Byzantines for simple desert Arabs who tended to equate splendor and power. In addition Abd al-Malik intended to make a symbolic statement to both Jews and Christians, the two religions that Islam considered its imperfect predecessors. His building spoke to Jews by its location, to Christians by its interior decoration.
In addition to the memory of its association with the Temple, Jewish legend had endowed the rock with a complex mythology centring round the figures of Abraham and Isaac. By building above it, Abd al-Malik appropriated the rock and its Abrahamic resonances for Islam. The message to Jews was that their faith had been superseded. The message to Christians was no less clear. The diadems and breastplates represented in the mosaic decoration are the imperial jewels of Byzantine rulers or the ornaments worn by Christ, the Virgin and saints in Byzantine religious art. These symbols of holiness and power are in the sanctuary of an alien faith, like the Persian crowns, because they are the spoils of the victor.
Source: The Holy Land by Jerome Murphy- O’Connor