Multiplan was an early spreadsheet program developed by Microsoft. Known initially by the code name "EP" (for "Electronic Paper"), it was introduced in 1982 as a competitor for VisiCalc.
Multiplan was released first for computers running CP/M; it was developed using a Microsoft proprietary pseudo code C compiler as part of a portability strategy that facilitated ports to systems such as MS-DOS, Xenix, Commodore 64, Texas Instruments TI-99/4A, Radio Shack Model II, Apple II, and Burroughs B-20 series.
Despite the release of Microsoft Chart, a graphics companion software, Multiplan continued to be outsold by Lotus 1-2-3. It was replaced by Microsoft Excel which followed some years later on both the Apple Macintosh (1985) and Microsoft Windows (1987).
Around 1983, during the development of the first release of Windows, Microsoft had plans to make a Windows version. However the plans changed a year later.
The Commodore 64 version was published by Epyx and as such, used their Vorpal Fast Loading technology. It looks like this may have been the first release as it contains a "HesWare" disk.