From Smith's Dictionary of Greek and Roman Biography and Mythology (London, 1880)
ACADE'MUS (Academos), an Attic hero, who, when Castor and Polydeuces invaded Attica to liberate their sister Helen, betrayed to them that she was kept concealed at Aphidnae. For this reason the Tyndarids always showed him much gratitude, and whenever the Lacedaemonians invaded Attica, they always spared the land belonging to Academus which lay on the Cephissus, six stadia from Athens. (Plat. Thes. 32 ; Diog. Laert. iii. 1. § 9.) This piece of land was subsequently adorned with plane and olive plantations (Plut. Cim. 13), and was called Academia from its original owner.
An original e-text for everything2. I scanned, OCR'd, formatted, and linked this text - it is not available in any format on any other web site. All Greek words are transliterated into Latin characters.