A number of sources contend that the khat tree originated in Harar, an Arab town in the Ethiopian hills. The Ethiopians are believed to have brought the tree to the Yemeni city of Ta'izz in 1222, but precise documentation is unavailable. Exactly when khat began its long journey from an innocuous and unnoticed tree to today's cultural mainstay is a mystery, but it seems likely that religious men first discovered its properties, using it to ward off sleep during long, nighttime meditations, and carrying it with them on missionary journeys.