One of Bill Gate's successors at Microsoft, Craig Mundie, has taken on a new role as senior advisor to the CEO in preparation for his retirement from the company in 2014.

The former chief research and strategy officer will report directly to Steve Ballmer in his new role after having served Microsoft for 20 years.

"In this role, he works on key strategic projects within the company, as well as with government and business leaders around the world on technology policy, regulation and standards," says Mundie's updated biography on the Microsoft Web site.

The move was first announced in a Dec. 14 memo from Ballmer but had not been publicized until AllThingsD broke the news on Monday.

"Over his career, Craig has brought great value to the groups and initiatives he has started and overseen and now brings that wealth of experience to his new role," Ballmer said in the memo seen by AllThingsD. "Craig has also been instrumental in building relationships with governments and policymakers around the world."

Mundie, 63, was one of the two men hand-picked by co-founder Gates to take over leadership of the technical side of Microsoft when he retired from day-to-day work at the company in 2008.

During his time at the company, Mundie oversaw Microsoft Research, one of the world's largest computer-science research organizations, and was responsible for Microsoft's long-term technology strategy, directing a number of technology incubations.

For more than a decade, Mundie was Microsoft's principal technology-policy liaison to the US and foreign governments, with an emphasis on China, Russia, and India.

Mundie's job switch is the second major change to Microsoft's senior leadership within the past two months, following Windows boss Steven Sinofsky's resignation in November.

Eric Rudder, chief technical strategy officer, will take over some of Mundie's duties overseeing research, privacy and security, as well as technology policy. He was previously the SVP for Servers and Tools and oversaw Microsoft's relationship with software developers.