This is a bit of ancient history, but back when Munich decided to move away from Microsoft (only because MS dropped Windows NT 4.0), it is said that Ballmer tried first dropping license fees down to a whooping 90% for a limited time.

That didn't work, so MS started a campaign of FUD against Linux that lasted ten years (e.g. http://www.linuxinsider.com/rsstory/77174.html).

Then a year later, it was announced that MS would move its DACH headquarters to Munich and almost serendipitously, Munich also declared that it was moving back into Microsoft's arms for.. em.. pure bureaucratic reasons:
http://www.theinquirer.net/inquirer/news/3006352/munich-it-chief-slams-citys-surprise-decision-to-dump-linux-for-windows

For the love of Pete I don't remember from whom I heard it first or if I read it somewhere, but at a point Bill Gates was gloating about negotiating with Munich on behalf of Microsoft.

In any case, he never left:
https://www.windowscentral.com/microsoft/bill-gates-still-backstage-manages-microsoft