Olympia is a full range Italian brand founded by Carlo Borghi in 1893, making it the 2nd oldest Italian brand in continuous manufacture, after Bianchi. The company sponsored a pro team in the 1930s and 1940s, though I'm not aware of them having any major victories on the palmares. Circa 1960, it was acquired by the Fontana family, who continue to offer the marque, to this day.

As noted, the decal remnants are an Aelle decal from 1978+. However, I believe it actually a Tretubi Aelle decal. Based on the decal, in conjunction with the S/N, I believe the frame is from 1986. Overall, the workmanship and fittings are consistent with a lower mid-range Tretubi Aelle model, with the exception of the chromed head lugs. It would appear to be a touring/randonneur type frame based on the dropout eyelets, fender bolt and what appears to be a chain guard tab.