This paper will present new evidence to resolve a long-standing problem in the biography of Mani, the founder of Manichaeism, who lived in Sasanian Iran during the third-century A.D. There are a number of important early references to Armenia in Manichaean texts. These include a Sogdian account of how Mār Gabryab brought the religion to Armenia and contains the earliest known literary reference to the name of the capital city of Erevan; and various notices of Mani’s own Letter to Armenia in Arabic, Middle Persian and Sogdian. But the principal focus for this paper is to resolve the question as to whether Mani himself travelled to Armenia in the early/mid 270s A.D. The account of his final travels, before his imprisonment and death under King Bahrām I in Gondēšāpūr, has been the subject of sustained debate since late antiquity. The early Christian polemical tradition represented by the Acts of Archelaus (ca. 330 A.D., extant in Latin, with parallels and elaborated traditions in Greek, Syriac etc.) placed him in the mysterious Castellum Arabionis near the border of the Roman Empire, and in the 19th-century it was common to locate this in Armenia. However, discoveries of primary Manichaean texts in Coptic and Middle Iranian languages in the 20th century turned attention to sites in Mesopotamia. This paper aims to reconcile these accounts and will utilise a newly-edited Coptic source to demonstrate that Mani did, indeed, travel to Sasanian Armenia in the company of a local nobleman named Baat.