the Peloponnese
The large peninsula of southern Greece, home of Sparta and its allies.
Today: Peloponnese, Greece
The Plague at Athens, and Pericles Answers the Athenians
Thucydides, History of the Peloponnesian War, Book 2 (sections 47–65) · after 430 BCE (events of 430–429 BCE)
περὶ μὲν οὖν τοῦ χρηστηρίου τὰ γιγνόμενα ᾔκαζον ὁμοῖα εἶναι· ἐσβεβληκότων δὲ τῶν Πελοποννησίων ἡ νόσος ἤρξατο εὐθύς, καὶ ἐς μὲν Πελοπόννησον οὐκ ἐσῆλθεν, ὅτι καὶ ἄξιον εἰπεῖν, ἐπενείματο δὲ Ἀθήνας μὲν μάλιστα, ἔπειτα δὲ καὶ τῶν ἄλλων χωρίων τὰ πολυανθρωπότατα. ταῦτα μὲν τὰ κατὰ τὴν νόσον γενόμενα.
People supposed that events were matching the oracle. The sickness broke out just after the Peloponnesians invaded, and it never entered the Peloponnese to any extent worth mentioning. It spread most of all through Athens, and after that through the most crowded of the other places. Such were the events of the sickness.