The link between Baron Wolfgang von Strucker and Ultron has been revealed.
According to Marvel Studios president Kevin Fiege over at Entertainment Weekly, Tony Stark (Robert Downey Jr.) takes inspiration from Strucker's (Thomas Kretschmann) work to improve his own in Avengers: Age of Ultron.
“Von Strucker was working on a lot of stuff, including robotics. Tony realizes, ‘[Those robotics] might be able to help me get over the hump of some of the AI stuff I’ve been working on.’”
To this end, Ultron (James Spader) comes about as a result of work that Strucker started and Stark finished.
When Ultron goes bad, he uses Stark's familiar AI program J.A.R.V.I.S. to forge his own project: Vision (Paul Bettany).