The Mahāvyutpatti is traditionally attributed to the reign of Ralpacan (c. 838), "but as Professor Tucci has pointed out (Tombs of the Tibetan Kings, pp. 14–15), it undoubtedly goes back to his predecessor Sad-na-legs, and one might well assume, in its actual conception, even back to the time of Khri Srong-lde-brtsan, when these problems were first seriously confronted...." So, whatever the case, it must be dated prior to 838 CE, and probably to the time of Sadnalegs (reigned c. 800–815 CE).