Corrected entry: In the original X-Men, Professor X says Magneto helped him build Cerebro, which is how Mystique is able to infiltrate the system. First Class contradicts this by having Hank McCoy create Cerebro and Magneto having nothing to do with it.
Vader47000
15th Jun 2011
Correction: Hank McCoy invents, designs and builds the first prototype we see in the CIA base. The one under Xavier's mansion is clearly a different one. There's no reason Magneto couldn't have helped them [both Beast and the Professor] build that version during his stay in the mansion or even years later. Especially since he has powers which would come in very handy when manipulating large steel panels.
Overcracker