September 2013: Microsoft acquires Nokia
The history of Microsoft's mobile efforts arguably had no single bigger story than the acquisition of the internationally adored Nokia. Prior to this, Microsoft had struck an agreement with the Finnish phone maker to put Windows Phone on its devices, finally bringing Nokia a more modern solution than the, at this point, ancient Symbian.
So, for over $7 billion, Microsoft got itself a first-party smartphone brand that most could agree prolonged the life of Windows Phone and Windows 10 Mobile, albeit not for too long.
But at the time, this was the most exciting news Windows Phone fans could have imagined. Microsoft would not only make the platform but funnel its huge wealth into making phones. The future was bright. For a short time, anyway. The impact of the acquisition at the end of the decade is almost non-existent, as Microsoft's mobile efforts shift to Android, just like Nokia's.
