Claim: Marcion of Sinope (born AD 85) developed the ditheistic system of belief (the notion of two gods) in 144, and he entirely opposed the Tanakh.
Evidence: Marcion of Sinope (/ˈmɑːrʃən, -ʃiən, -siən/; Greek: Μαρκίων Σινώπης; c. 85 – c. 160) was an important figure in early Christianity. Marcion responded by developing a ditheistic system of belief around the year 144. By contrast, duotheism, bitheism or ditheism implies (at least) two gods. In contrast to other leaders of the nascent Christian Church, however, Marcion declared that Christianity was in complete discontinuity with Judaism and entirely opposed to the Tanakh.