David Imel / Android AuthorityTL;DR Microsoft reportedly had plans for a Surface-branded Windows Phone years before the Surface Duo, with a 2013-2014 prototype recently revealed. The mysterious phone featured a 720p display, physical navigation buttons, a silver Surface-like chassis, and Windows Phone 8.1. Microsoft’s Surface Duo and Surface Duo 2 were ambitious first attempts from a company that had little to no experience building smartphones all by itself. 2020’s Surface Duo, arguably, was Microsoft’s first smartphone designed and developed as a true first-party Surface device on its own terms. As we know now, the Surface Duo, and the later-released Surface Duo 2, took a novel approach.