1920's, the legends Gibson Luthier and Lloyd Loar were both working on a prototype bass. Based around a semi-solid upright bass, with electrostatic pickups, but it wasn't up to the job so Gibson did not put into production, however around the 1940s, Paul Tutmarc Jr designed the first fretted fully working electric bass guitar, known as the Serenader Bass, designed to be played horizontally. Find out more "dawsons.co.uk/blog/electric-bass-guitar-brief-history"