From Livorno to Leghorn and back again

• Can anyone tell me why the Tuscan city of Livorno used to be called Leghorn in English?

An increasing number of British writers, artists, philosophers, and travelers visited the area and developed the unique historical ties between the two communities. The British referred to the city as Leghorn.

^Wikipedia

I believe nowadays English brochures, foreign travellers etc. call the city by its traditional Italian name. So did the name Leghorn simply fell in popularity or disuse as suggested by Google Ngram? Did the Livornese hold a petition or protested?! (I've been living in Italy for over thirty years, and I don't recall ever hearing them complain.)

• What term is commonly used when an anglicized city's name reverts back to the original?

Solution 1:

On the origin (also this):

Leghorn
breed of fowl, 1869, from Leghorn, city in Italy (modern Livorno, 16c.-17c. Legorno), from Latin Liburnus, from the native people name Liburni, which is of unknown signification.

[ Online Etymology Dictionary ]

Ferdinando I de' Medici wrote "Liuorno" in 1593 (Document Inviting Jewish Merchants to Settle in Livorno and Pisa). In any case here is a discussion about the Livorno/Legorno difference (see also note therein):

In the fine Portolano of Carachi already mentioned, Legorno, Florentia and Neapolis appear for Livorno, Firenze and Napoli of the present day; and assuredly the classic enunciation of the last two cities assimilates more with the English names - also our adjective, Neapolitan - than with the modern Italian. Leghorn he has even written in Greek characters Λεγορνο [...]; and others of the same epoch(circa 1550) term it Legorne, Ligorna and Ligorno which last was adopted by Crescentio, in 1607.*

[ The Mediterranean: A Memoir Physical, Historical, and Nautical, Rear-Admiral William Henry Smyth, 1854(John W. Parker and Son), p. 409 ]

Aside from the "similar" spelling, Leghorn (even more so when /ˈlɛɡɔrn/) resembles Legorno (somewhat), at least more so than it does Livorno.

Maybe Leghorn was an exonym based on the classic enunciation and geographical renaming occurred.