Microsoft and Google, sworn rivals in the computer industry, have joined forces to sue a geolocation technology firm GeoTag Inc over a patent issue.

Texas-based GeoTag Inc has been chasing users of Microsoft Bing Maps and Google Maps. It has already sued more than 390 companies, including Boeing, Rolex and Pizza Hut, claiming patent violations.

But, Microsoft and Google are now claiming that the patent, Internet Organizer for Accessing Geographically & Topically Based Information, should not have been granted because of the existence of ‘prior art’. The patent in question involves using mapping services to build store locators and related locator services on websites.

The duo want the US District Court for the Eastern District of Texas to overturn GeoTag’s concerned patent and rule that the Bing Maps and Google Maps users didn’t violate GeoTag’s geo-location patent. In addition, they are demanding recovery of costs and fees.

The patent in question was originally filed in 1996 and granted in 1999. It was sold and re-sold many times. Around two years back, the patent was re-sold for $119 million to electronic payment services firm Ubixo, which in July last year spun off GeoTag as a separate company.