Microsoft announced today that it was acquiring Bellevue-based Intentional Software for an undisclosed amount of money. With the purchase, Charles Simonyi, Intentional founder, Chairman, and CTO, who helped develop some of Microsoft’s famous Office tools like Excel and Word returns to Microsoft.

Simonyi left Microsoft in 2002 to launch Intentional. While it’s not crystal clear what Intentional does, according to a Microsoft blog post announcing the deal, it began looking at ways to simplify programming and later did some work “to develop productivity scenarios for the future workforce.” If that seems vague to you, you’re not alone, but apparently the company brings some expertise to Microsoft on working in groups, an area Microsoft has been pursuing lately with the launch of Microsoft Teams (and let’s not forget it purchased Yammer in 2012 for $1.2 billion, as well).

In a blog post announcing the deal, Rajesh Jha, executive vice president for the Office Product Group said he was excited about the acquisition, just as you would expect. “We’re excited about the company’s work on productivity applications, especially given our focus of putting people at the center of experiences and our continued effort to reimagine collaboration,” Jha wrote.

Simonyi gets a bit more specific in his blog post on the acquisition. He sees a world where collaboration can be combined with hardware technology like the Surface and machine learning and exciting things could begin to happen.

“Imagine then, the power of an ontology consisting of thousands of terms covering most of the common activities that comprise our personal and professional lives ranging from life transitions, education, entertainment, buying and selling. Curating and exploiting such an ontology will be as important as the hardware and software surfaces that activate it,” Simonyi wrote.

Simonyi didn’t just help develop Excel and Word, he’s also been to the International Space Station a couple of times, spending 25 days in space in two trips in 2007 and 2009. He also flies helicopters and multi-engine planes.

While none of that will probably come in handy when he returns to Microsoft, it sees his company and his team as a valuable addition, at least from a research and development perspective.

The parties involved were certainly effusive about the deal with Intentional CEO Eric Anderson writing, “In this next chapter, I see the potential for an even greater impact. The world is bigger, more connected, and technology is far more sophisticated and far more accessible.”

The deal will be subject to regulatory approval, and while Microsoft has changed significantly since Simonyi last worked there, it certainly seems like this would be a smooth transition as his team becomes part of Microsoft.