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Dates from early 1960's. Frame constructed with Agrati lugset model "AM." Head is bulge-formed. 1964 was approximately the final year for the bicycle's Ambrosio I-beam stem. There are different generations of the bicycle's Campagnolo Gran Sport rear derailleur. It enjoyed a relatively long production life. You may be able to bracket the dating a bit narrower by comparing it to the ones shown at Velobase.com:

VeloBase.com - Component: Campagnolo 1012/1, Gran Sport

VeloBase.com - Component: Campagnolo 1012/4, Gran Sport

Do hubs have a "Simplex" mark on their barrels? Suspect they may be five-piece steel made for Juy by FB. Pedals look like Sheffield model 663. Chainset Magistroni, regardless of how marked.

Regarding branding - cycle could be a contract build done for an importer or chain store. May not be a "real" brand in the sense of their being a cycle manufacturer with that name.

If you could post an even larger format photo of the partial seat tube transfer it might advance the detective work of readers.

Have had a number of different Italian bikes from this time come through my workshop which were identical "in the metal" to yours. All wore different brand names.

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