Microsoft has agreed a deal to buy Nokia's
mobile phone business for 5.4bn euros ($7.2bn;
£4.6bn).
Nokia will also license its patents and mapping services to Microsoft. Nokia shares jumped 35% on the news, whereas Microsoft's fell more than 5%.
The purchase is set to be completed in early 2014, when about 32,000 Nokia employees will transfer to Microsoft.
Nokia has fallen behind rivals Samsung and Apple, while critics say Microsoft has been slow into the mobile market.
Describing the deal as a "big, bold step forward", Microsoft chief executive Steve Ballmer told the BBC that his company was in the process of transforming itself from one that "was known for software and PCs, to a company that focuses on devices and services".
Nokia Timeline
1871: Founded. Spends the next century making tyres, boots and cables.
1987: Launches first phone. The Mobira Cityman weighs almost 1kg.
1992: Sells non-mobile divisions and launches first digital GSM phone, the Nokia 1011.
2000: Stock market value hits 186bn euros. Now worth 11bn euros.
2003: Basic 1100 phone launched. Goes on to sell 250 million units and become the world's most popular consumer electronic device.
2011: Abandons Symbian mobile phone operating software and switches to the Windows platform instead.
2013: Launches the Lumia 1020 boasting a 41 megapixel camera.
Source: Reuters/Nokia