How the mighty have fallen. A brand once synonymous with the word cellphone has become just another product in Microsoft's vast stable.

The process that led to Nokia, once a world leading handset and services business, becoming a segment of Microsoft multi-billion dollar empire will be completed April 25. It began in September 2013 when Microsoft said it would purchase Nokia's devices and services business for $7.2 billion. April 25 will finally see Nokia exit a business it once dominated and mark the end of an era.

Microsoft executive vice president and general counsel Brad Smith announced the closing of the deal in a blog post on Monday. He said the completion of this acquisition follows several months of planning and will mark a key step on Microsoft's journey towards integration.

"This acquisition will help Microsoft accelerate innovation and market adoption for Windows Phones," he said.

One of the few tweaks to the original deal will see Microsoft manage the Nokia.com domain and social media sites for at least one year. Also, Microsoft will not buy Nokia's Korean manufacturing facility that was part of the original deal.

Microsoft said it would acquire some 32,000 Nokia employees. Among these are 18,000 employees involved in the manufacturing of devices. As part of the deal, Nokia will also transfer of some of its patents to Microsoft.

Former Nokia CEO Stephen Elop now heads Microsoft's Devices and Services unit and reports to Microsoft CEO Satya Nadella.

Nokia's acquisition will accelerate the roll-out of Microsoft's Window Phone operating system for smartphones. Window Phone's share of the global market for smartphone OS' stands at just 3.9 percent. Research firm IDC expects that share to hit seven percent by 2018.

The market share held by Windows Phone competitors, Android and iOS, is expected to fall from 78.9 percent to 76 percent and from 14.9 percent to 14.4 percent, respectively.