Passage 2.35.2
καὶ ἐπʼ αὐτοῦ θύουσιν Ἑστίᾳ. Ἀπόλλωνος δέ εἰσι ναοὶ τρεῖς καὶ ἀγάλματα τρία· καὶ τῷ μὲν οὐκ ἔστιν ἐπίκλησις, τὸν δὲ Πυθαέα οὕτως ὀνομάζουσι, καὶ Ὅριον τὸν τρίτον. τὸ μὲν δὴ τοῦ Πυθαέως ὄνομα μεμαθήκασι παρὰ Ἀργείων· τούτοις γὰρ Ἑλλήνων πρώτοις ἀφικέσθαι Τελέσιλλά φησι τὸν Πυθαέα ἐς τὴν χώραν Ἀπόλλωνος παῖδα ὄντα· τὸν δὲ Ὅριον ἐφʼ ὅτῳ καλοῦσιν, σαφῶς μὲν οὐκ ἂν ἔχοιμι εἰπεῖν, τεκμαίρομαι δὲ περὶ γῆς ὅρων πολέμῳ σφᾶς ἢ δίκῃ νικήσαντας ἐπὶ τῷδε τιμὰς Ἀπόλλωνι Ὁρίῳ νεῖμαι.
Upon it they sacrifice to Hestia. There are three temples and three statues of Apollo. One of these has no special epithet, another they name Pytheus, and the third is called Horios ("of Boundaries"). They learned the name Pytheus from the Argives, for, according to Telesilla, Pytheus, a son of Apollo, was the first among the Greeks to come to their land. As for the one they call Horios, I cannot say precisely why they gave him this name, but I conjecture that they so honored Apollo under the title "Horios" after winning, whether by war or in arbitration, some dispute over territorial boundaries.