Telemachus. He is said to have given his name to Latium, the homeland of Rome, although Latinus actually ruled, we are told, at Laurentum, which was refounded a short distance away as Lavinium, a name given in honour of Latinus' daughter Lavinia.
More obviously, of course, the name relates to 'Latin', which properly was the name of the language spoken by the people (the Latini) who inhabited Latium. (Originally this was a small area in west Italy in which Rome lay.) It is possible that the name (and thus Latin and Latium) could be related to latus, 'broad', 'wide'.