Original: Marcionism is an type of Christianity which started around 144 ( 115 years and 6 months after the Crucifixion of Jesus , according to Tertullian 's reckoning in Adversus Marcionem , xv ) .
Simplified: Marcionism is an type of Christianity which started around 144 ( According to Tertullian in Adversus Marcionnem , it started 115 years and 6 months after the Crucifixion of Jesus ) .