The Dome of the Rock marks a specific journey in Islamic tradition, and for nearly a century during the Crusades it was used for an entirely different religion's worship.
The night journey
Islamic tradition holds that Muhammad was carried by night from Mecca to "the farthest mosque," identified with this site, in the Isra, and from there ascended through the heavens in the Mi'raj, meeting earlier prophets before returning the same night. This account, referenced briefly in the Quran and elaborated at length in hadith literature, is the specific religious event the Dome of the Rock was built to commemorate, distinct from the platform's separate significance in Jewish and Christian tradition.
Converted, then reconsecrated
When Crusader forces took Jerusalem in 1099, the Dome of the Rock was converted into a church known as the Templum Domini, and the nearby al-Aqsa Mosque served for a period as headquarters and residence for the Knights Templar, whose name derives directly from that use. When Saladin retook Jerusalem in 1187, both buildings were restored to Islamic use, an episode of roughly ninety years, in which the platform's Islamic status was interrupted rather than continuous.
Some of the oldest surviving Quranic inscriptions
The Dome of the Rock's interior carries monumental Quranic inscriptions in early Kufic script dating to its original construction around 691 CE, making them among the oldest surviving physical texts of the Quran displayed in this form anywhere.