How long did the battle of Troy go for?

Answer 1

For several weeks. The Iliad indicates that after an initial failed attack, the Greeks went off pillaging the coast and islands of Asia Minor and came back when everything was all looted out at have a final go at Troy.

The Iliad deals with only a short segment of the saga of the Trojan War. The actual war, if it happened, was said to have continued for ten years. === === This was therefore not a Trojan War, but an ongoing organised piratical raid, in which Troy was but one of many targets, at least according to the legend as it has come down to us from a myriad of oral and written fragmentary sources. One must try to separate oral tradition (legend, if you will) from later sources, such as Diodorus Siculus, who may have been working from some oral tradition or may have been doing to the Trojan War legend what Mallory did to the Arthurian one. No one knows for sure.

What is certain is that the king of Hatti, to whom Wilusa (Troy) was a vassal state, mentioned in a surviving diplomatic text to the king of the Greeks (or at least part of the Greeks) that there had been trouble over Wilusa that was now settled between the two kings. That there had been ongoing friction between the Greeks and Hittites is certain, and that any large-scale siege of a city as well fortified as Troy would have required raids in and around the islands and west coast of modern Turkey is also certain. What is not certain is that there was, or was not, a Trojan War.

Answer 2

According to the legend, only a few months. At the beginning of a series of piratical raids in the eastern Aegean Sea and Asia Minor, they made an attempt on Troy which failed. Ten years later they returned and were successful in capturing the city after a couple of months by a strategem. Or so the legend goes.