The brandname Welson was used by the Italian Quagliardi company, established in Castelfidardo the 1920s. Like many instrument factories in the area, it was originally an accordian maker. The first Welson brand guitars were acoustic archtop models which appeared in the 1950s,. By the early 1960s there were also Welson solid body electric guitars. From the mid sixties onwards, Welson's focus shifted to semi-acoustic archtops aimed at professional musicians. In the early 1970’s there were Welson brand Les Paul and SG copies, and then later in the 1970s the Quagliardi company moved into in electronic keyboards. There were still some high quality guitars made to order during the 1970s in the Quagliardi workshops. By 1981 the Quagliardi company stopped trading altogether.

Source: The Welson guitar brand at fetishguitars.com