Re mine and his, it's because Barcelonia is a common, though minor and generally foreign (but not French?), spelling of Barcelona, now fallen into disusual. E.g.g.:
- The Kinges Commission for the Imbarment of All English Ships. [Translated from the Spanish.] (At Barcelonia, 29 May [1585].).
- Horatii Tursellini, Historiarum ab origine usque ad annum 1598 (1653), Barcelona:Barcelonia = 1:1: "Cum Mareschalis Bresaeus esset in urbe Friguet post fugam Hispanis datam, ingressum in Barcelonia facere statuit"
- Leonis ab Aitzema, Historia pacis, a foederatis Belgis ab anno 1621 ad hoc (1654), 0:1: "D. Philippus, Dei Gratiâ, Hispaniarum Rex, &c. Archi-Dux Austriae, Dux Burgundiae, Brabantiae, Mediolani, Comes Absburgi, Flandriae, Tyrolis, Barceloniae & Molinae Dominus, &c."
- Hieronymus Scheidt, Kurtze und warhafftige Reise-Beschreibung, Der Reiß von Erffurt auß Thüringen nach dem gewesenen gelobten Lande, und der Heil. Stadt Jerusalem (1670), 0:1: "Weiter liessen wir das Land Catalonien auf der rechten Hand liegen / die Hauptstadt desselbigen / wird Barcelonia genant / ist eine reiche fruchtbare Landschaft"
- Pieter Schrijver, Hollandsche, Zeelandsche ende Vriesche chronyck (1677), 1:1: "Op den laetsten van Mey trock de Infante van Spangien met haeren Man Albertus, Eertz-Hartogh van Oostenrijck, van Valencen daer sy ghetrouwt waren, naer Barcelonia, ende is aldaer den 8. Junii t' Scheep ghegaen"
- James Howell, Epistolæ Ho-Elianæ (1688), 3:1: "I am now in Barcelonia, but the next Week I intend to go on through your Town of Valentia to Alicant"
- Francisco Giustiniani, El nuevo Atlas Universal abreviado (1755), 8:1: "Es Patria Barcelonia del Poeta Boscan y del famoso Capitan Francisco Calvo-Gualbes, el qual vinciò a los Moros"
- Edmund Burke, Annual register (1762), 0:1: "four large and beautiful causeways are likewise ordered to be made from Barcelonia, Cadiz, Valence, and Gallicia, leading to Madrid"
- William Guthrie, New Geographical, Historical, and Commercial Grammar (1795), 6:1: "The court was then at Barcelona: Columbus travelled thither from Seville, amidst the acclamations of the people, attended by some of the inhabitants, the gold, the arms, the utensils, and ornaments of the country he had discovered. This entry into Barcelonia was a species of triumph more glorious than that of conquerors, more uncommon, and more innocent."
- Edward Gibbon, Decline and fall (1816; I haven't checked earlier editions), 2:1: "[Wallia] marched in arms, from Barcelonia to the shores of the Atlantic Ocean"
- Noah Webster, Dictionary (1831): "the mensuration of degrees of latitude between Dunkirk and Barcelona"; "Barcelonia livres"; (but also "Barcelona, Sarogossa, Valencia")
So it's a common misspelling, you will say. Perhaps not, I will protest, because Philippe Olinger's Nieuw Fransch en Nederduitsch [i.e. Dutch] woordenboek (1828) has "BARCELONE, f. Barcelonië."
Why, why, why? Retarded printers starting shifts in the early hours? Hypercorrection based on limited Latin?