'''Tachkastan''' (also known as '''Tashik''' in Tang Chinese and '''Tayyaye''' in Syriac '''Tayy''' in Arabic) was a [['''Quasi-Manichean Noahite]] ''' state of Erev Rav in the Iraqi desert which gained independence under a Noahite faction at the battle of Dhi Qar in 622, (the year of the Arabs ) and grew into the Umayyad Caliphate. Its capital was in the province of Orientalis otherwise known as Al-Jazizah, Iraq between the Persian and Roman Empires. Sebeos tells us that it was tho this desert that the [[Jews of Edessa]] were sent by Heraclius soon after his victory in 628. In Tachkastan the exiled Edessan Jews were welcomed bu certain Edomean-Ishmaelite believers in Judaism who they Jews were unable to rally to their cause until a new leader reose to power in 634.
Many Edomeans and Ishmaelites had been converted into Jews and Sadducees from Hasmonean times (under John Hyrcanus and John Alexander) as well as under the Himyarite Kingdom where they adopted the Judeo-Arabic term MHMD for the Mem Tet (Messiah ben Joseph) of the Mahamadim described in the Shiur Qomah.
