In Greek mythology, how long did the Trojan War last?

For most ancient Greeks, indeed, the Trojan War was much more than a myth. It was an epoch-defining moment in their distant past. As the historical sources (Herodotus and Eratosthenes) show, it was generally assumed to have been a real event.

According to Homer’s "Iliad", the conflict between the Greeks (led by Agamemnon, King of Mycenae) and the Trojans (whose king was Priam) took place in the Late Bronze Age, and lasted 10 years. It began when Paris, Priam’s hapless son, judged Aphrodite to be the most beautiful goddess, for which she gifted him Agamemnon’s gorgeous sister-in-law, Helen in return. Determined to get Helen back and punish the Trojans, Agamemnon and his brother marched a mighty army against Troy, and eventually succeeded in bringing its people to their knees.