Italy, Holland, USA, Australia and England all had distinct Simplex brands. This is the one from Italy. The Simplex Ala D'oro (Gold Wing) was built in Turin between 1921 and 1950. They built several models using their own OHV engines in 149, 174, 210 and 496cc sizes and new for 1937 is suspension.
Apparently post-war more motorcycles were assembled from existing stock in 148cc and 248cc sizes.