King Teucer (Teukros), son of the river-god Scamander and the nymph Idaea, is the first king of the land later called the Troad. Before Dardanus arrived the country was Teucria and its people Teucrians; Teucer gave his daughter Batea (Batia / Arisba) to Dardanus and, dying without a son, left the realm to be absorbed as Dardania. The atlas keeps him distinct from Teucer the Salaminian archer, son of Telamon.
Adapted from Wikipedia, "King Teucer" · CC BY-SA 4.0
I.Origins and settlement
Before Dardanus came, the land that became Dardania and later the Troad was known as Teucria after Teucer, son of Scamander and Idaea. Virgil brings him from Crete during a famine with a third of the island's people; Dionysius of Halicarnassus instead derives him from Attica as a chief of Xypete. In both strands he settles beside the Scamander near the Rhaetean promontory.
His company was plagued by mice on the first night. An oracle had told him to settle where an earth-born enemy attacked by night; taking the mice as that omen, he founded Hamaxitus and built the first temple to Apollo Sminthius — Apollo the destroyer of mice.
II.Family and succession
His only child, Batea (also Batia or Arisba), married Dardanus. When Teucer died without a biological son, Dardanus received land on Mount Ida, founded Dardania, and absorbed Teucer's kingdom; the whole region took Dardanus's name though the people remained Teucrians in speech.
Diodorus calls him the first to rule as king over the land of Troy; Virgil's Anchises recalls him as the Trojans' first forefather. This node is teucer-troas — not the Salaminian hero teucer, half-brother of Ajax.