In the 1920s Poland began looking for a new standard military pistol, and tested a variety of compact .380s. The representative from FN brought along an early iteration of the High Power (along with their other entry) even though it was much too large and heavy to meet the Polish requirements. After a couple iterations of testing, it became clear to the Polish Ordnance officers that the High Power was a much more effective service pistol than the compact guns they had been instructed to look for.
Lo and behold, the ultimate choice was a domestic design based largely on the High Power (a direct deal with FN was not an option after Poland's relationship with FN had suffered through problems with the wz.28 version of the BAR). Toss in a delay to redesign the early decocking mechanism to satisfy the Cavalry (who didn't realize that the decocker wasn't actually meant to be used, but rather to just add another claim to the patent), and by 1935 the pistol was finished and formally adopted.
The Vis 35 is one of the best automatic pistols of WWII in terms of both handling and quality. In total 46,000 were made pre-war for Poland's military, and German occupation forces built another 300,000+ during the war.