Short answers, pulled from the story.
Three engineers named Servan Keondjian, Doug Rabson, and Kate Seekings founded a company called RenderMorphics in 1992. The team built an application programming interface known as Reality Lab to handle complex three-dimensional graphics for medical imaging and computer-aided design software.
The first version of Direct3D shipped with DirectX 2.0 on the 2nd of June 1996. This release followed by DirectX 3.0 on the 26th of September 1996 marked the initial availability of the API for Windows 95 development.
DirectX 8.0 released in November 2000 introduced programmability through vertex and pixel shaders for the first time. Developers could now write code without worrying about superfluous hardware state because display drivers compiled these shaders into instructions understood by the hardware.
DirectX 12 released as part of Windows 10 enabled lower-level hardware abstraction to improve multithreaded scaling and reduce CPU utilization. Command lists replaced sequential command sending, allowing the GPU to compute entire packages without waiting for additional information from the processor.
WineD3D provided working implementations of Direct3D APIs through translation to OpenGL for non-Windows platforms while vkd3d built an open source library atop Vulkan to allow Direct3D 12 applications to run over Vulkan infrastructure. Valve's Proton project included DXVK as part of Steam on Linux systems enabling modern Windows games to operate natively.