Strange Tales #115 Dec 1963
"The Origin of Doctor Strange"
Doctor Stephen Strange is a famous surgeon who works only for money, not caring for his patients nor interested in medical research.
An auto accident damages the nerves in his hands severely and he can never perform an operation again.
The proud Strange refuses to work for others and ends up on the street.
He learns about the healing powers of the Ancient One and travels to his sanctuary in India.
The Ancient One refuses to heal Strange because of his selfish motives,
but sudden snow forces Strange to remain in the sanctuary until the snow thaws.
Here he witnesses the Ancient One's pupil, Baron Mordo, launch magical attacks upon his master.
Mordo casts a spell upon Strange to stop him from warning the Ancient One of the attacks' origins.
Strange, therefore, resolves to learn the secrets of black magics to defeat Mordo himself.
The Ancient One accepts Strange as his disciple and dispels Mordo's spell, which he had known about all along.
Script by Stan Lee (co-plot, script) and Steve Ditko (co-plot, un-credited),
art by Steve Ditko