Richard Coates, in the 1998 article where he published his own theory of the etymology, lists all the known occurrences of the name up to around the year 900, in Greek, Latin, British and Anglo-Saxon. Most of the older sources begin with Londin- (Λονδίνιον, Londino, Londinium etc.), though there are some in Lundin-. Later examples are mostly Lundon- or London-, and all the Anglo-Saxon examples have Lunden- with various terminations. He observes that the modern spelling with <o> derives from a medieval writing habit of avoiding <u> between letters composed of minims.
The earliest written mention of London occurs in a letter discovered in London in 2016. Dated AD 65–80, it reads Londinio Mogontio which translates to "In London, to Mogontius".