On the compass card, and so surmounted it with the fleur-de-lys, traditionally chosen for that purpose on the compass by Flavio Gioja in honour of Charles of Anjou, king of Sicily and Naples.
Dependent upon the seaman's observation of the heavens, for these charts were in use long before the compass had been introduced on board ship (as early as 1205, according to Guiot de Provins) although it became fully serviceable only after the needle had been attached to the compass card, an improvement probably introduced by Flavio Gioja of Amalfi in the beginning of A.
Osann, De Flavio Capro (1849), and review by W.
Keil, "De Flavio Grammatico," in Dissertationes Halenses, x.
From this passage arose a legend, which took shape only in the 17th century, that the compass was invented in the year 1302 by a person to whom was given the fictitious name of Flavio Gioja, of Amalfi.
The term was first used in this sense by Flavio Biondo, whose "decades" was an attempt to block out the annals of history from 410 to 1410.