Why were the princes of Greece bound to help Menelaus get Helen back from Troy? Whhy were they eager to help?

The princes of Greece were bound to help Menelaus get Helen back from Troy primarily because of an oath taken by her suitors. Before Helen married Menelaus, all of her suitors made a solemn vow to support the man she chose in the event of any conflict arising from her choice. This oath was initiated by Odysseus, who proposed that all suitors should promise to defend the chosen husband against any wrongdoers. When Paris, a Trojan prince, abducted Helen from Menelaus, the situation called for the suitors to uphold their vow. The need to support Menelaus was not only driven by loyalty but also by a sense of obligation to honor their sworn oath. Additionally, the suitors were motivated by the prospect of glory and honor, as participating in a war against Troy promised them a chance to achieve fame and status. Many of the princes also had their own grudges against Troy or sought to strengthen their own positions through alliance and conquest. The combination of honor, obligation, desires for glory, and shared enmity against Troy thus fueled their eagerness to support Menelaus in the quest to retrieve Helen.