The Trojan Battle Order in Book II of the Iliad organizes Troy's allied contingents the way a modern military planner might organize an order of battle: by commander, by origin, by strength. Zeleia's entry is brief but specific. Pandarus, son of Lycaon — not the same Lycaon who was a son of Priam — led the men of Zeleia to war. Homer's text further describes them as 'Lycians,' a designation that has puzzled commentators ever since, because the Zeleians were clearly distinct from the Lycians from Lycia in southwestern Asia Minor who fought under Sarpedon and Glaucus. The label may reflect an older geographic or ethnic terminology that Homer inherited rather than invented. What is clear is that Zeleia sent real soldiers to a real war, or at least that the tradition remembered it doing so. Homer also calls the town 'holy' — a designation that implied a sanctuary or divine presence of some kind, though what deity was worshipped at Zeleia is not recorded in surviving texts.

In May 334 BC, with Alexander of Macedon having crossed the Hellespont and marching down the Asian coast toward them, the Persian satraps of the region needed to decide what to do. They gathered at Zeleia, and the historian Arrian — writing centuries later but drawing on reliable sources — records this council as the headquarters meeting before the Battle of the Granicus. The satraps debated their options: some wanted to avoid open battle and let Alexander's supply lines exhaust themselves; others argued for a direct engagement at the river. The battle faction prevailed. The Persian cavalry and infantry took position along the steep eastern bank of the Granicus, and Alexander attacked anyway, in what would become one of the most celebrated cavalry charges in ancient history. The Persians lost. Their satrapal administration of Hellespontine Phrygia — of which Dascylium, not Zeleia, was the capital — effectively collapsed in a single afternoon. Zeleia appears in the record of that council as a functioning town with the facilities to host a military assembly. After Arrian's account, the city fades from the sources.

Strabo, writing in the 1st century BC, mentions Zeleia as a place that still existed in his day — but by his account it had already declined from whatever prominence it once held. The geographer's description places it consistently with the Homeric reference: on the Aesepus River, south of the Propontis, in the landscape of the ancient Troad. Its membership in the Delian League — the Athenian-led alliance of the 5th century BC — is attested in the tribute lists that Athenian officials kept, which suggests a genuine polis with the administrative capacity to pay regular tribute to Athens. A figure named Nicagoras of Zeleia is recorded as a tyrant of the city at some point, which confirms it had a governing class and a political history, even if the details are lost. After Strabo, nothing more is recorded. The city seems to have been absorbed into the surrounding rural landscape of Mysia without leaving the kind of monumental remains that draw archaeological attention. Its identification with the site near Sarıköy remains the scholarly consensus, but excavation has been limited.

The Aesepus River — today called the Gönen Çayı — is perhaps Zeleia's most persistent legacy. The river itself appears in the Iliad as a proper noun, named and geographic, which means it was part of the poetic tradition's well-known landscape. Zeleia's men had drunk its water, Homer says, in the formulaic phrase that grounds warriors in their homeland before sending them to die. The Aesepus runs northward from the slopes of Mount Ida through the landscape that was once the Troad and Mysia, passes close to the site of Zeleia near Sarıköy, continues under the arches of the ancient Roman bridge known as the Aesepus Bridge upstream from modern Gönen, and reaches the Sea of Marmara a few kilometers north of where that bridge stands. The river is the connective thread linking the ancient Homeric geography to the Roman infrastructure to the modern agricultural plain: still the same water, flowing through the same valley, past the site of a city that Homer thought worth naming and that Alexander's enemies thought worth gathering in, now surrounded by rice paddies and the silence of a landscape that has long since moved on.