Inspired by an article on archeological finds from 1957. Patrick McGovern describes residues found in drinking vessels in what might be the burial site of King Midas of Phrygia, 8th century BCE, as containing "a highly unusual mixture of grape wine, barley beer and honey mead"
https://www.penn.museum/sites/biomoleculararchaeology/?page_id=143
Malt type and grape cultivar were not chosen based on any historical data, but on the author's taste. It's also a first attempt. Hops as a more affordable bittering agent was chosen over pure saffron for economical reasons.
The first attempt went down to 1.013 SG as opposed to the 1.026 Brewersfriend estimates.