“Portrait of a Young Man Holding a Roundel” dates to around 1480, and its sale is the art market’s biggest test of the new year.“Portrait of a Young Man Holding a Roundel” dates to around 1480, and its sale is the art market’s biggest test of the new year.Read MoreAuctions, Art, Quarantine (Life and Culture), Young Man Holding a Roundel, Botticelli, Sandro, Sotheby’s, Solow, Sheldon H, Manhattan (NYC)