Final answer:
Apollinaris made the error of suggesting that Jesus Christ had a divine mind but not a human one, which led to his views being condemned as the Apollinarian heresy.
Step-by-step explanation:
In his well-intentioned efforts to combat Arianism, Apollinaris made the error of proposing that Jesus Christ had a divine mind but not a human one, essentially suggesting that Christ was not fully human. This notion was seen as overcompensating in the fight against Arian beliefs, which claimed that Christ was a creation of God the Father and therefore subordinate. Apollinaris' view undermined the orthodox position that Christ was both fully human and fully divine, leading to his ideas being condemned as the Apollinarian heresy.