Final answer:
The Greek princes were obligated to help Menelaus due to a sacred oath of loyalty, and their cultural emphasis on honor made many eager to fulfill this commitment.
Step-by-step explanation:
The princes of Greece were bound to help Menelaus primarily because they were bound by a sacred oath of loyalty. The oath was formed during the time of crisis when most of the Greek city-states united against the Persian invasion. Furthermore, Greek honor and cultural values held significant sway over the decisions of Greek princes, making many eager to uphold their sworn promises and maintain their personal and collective honor.
The princes of Greece were bound to help Menelaus because they were bound by a sacred oath of loyalty. Many were eager to help because they were eager to uphold their honor.