Passage 2.29.8
οὕτως Αἰακοῦ δεησομένους ἀποστέλλουσιν ἀφʼ ἑκάστης πόλεως· καὶ ὁ μὲν τῷ Πανελληνίῳ Διὶ θύσας καὶ εὐξάμενος τὴν Ἑλλάδα γῆν ἐποίησεν ὕεσθαι, τῶν δὲ ἐλθόντων ὡς αὐτὸν εἰκόνας ταύτας ἐποιήσαντο οἱ Αἰγινῆται. τοῦ περιβόλου δὲ ἐντὸς ἐλαῖαι πεφύκασιν ἐκ παλαιοῦ καὶ βωμός ἐστιν οὐ πολὺ ἀνέχων ἐκ τῆς γῆς· ὡς δὲ καὶ μνῆμα οὗτος ὁ βωμὸς εἴη Αἰακοῦ, λεγόμενόν ἐστιν ἐν ἀπορρήτῳ.
Thus they dispatched envoys from each of the cities to ask for Aeacus' aid; and he, having sacrificed and prayed to Zeus Panhellenios, caused rain to fall upon the Greek land. When they arrived back from him, the Aeginetans had these statues made. Inside the enclosure olive trees have grown from ancient times, and there is an altar only slightly raised from the ground; but the idea that this altar is also the tomb of Aeacus is told as a secret mystery.