The Trojan War may be the earliest sea-crossing war, but due to the lack of historical records and insufficient understanding of this history, it is not considered for the time being. The war of crossing the sea, which was recorded in detail in history, was still related to Greece, that is, the famous Greek-Persian war, which took place in the 5th century BC, that is, in 490-480 BC, the Persian king Darius I launched the war, and Athens alone faced the powerful Persians (Greece was still a city-state). As a result, the Greeks used the flank surprise attack tactics to defeat the Persians in the Marathon Plain. At that time, there was a naval battle between the Athenians and the Persians, and finally the Athenians won. After the victory of this campaign, there is a tidbit about the origin of marathon. Around 480 BC, Xerxes I, the heir to the Persian king, led an army to attack Greece again. At this time, unlike the 1 Greece-Persia war, the Greek States joined forces to fight against aggression, including the very tragic "Hot Spring Pass Campaign". If you don't know, you can watch Sparta 300 Warriors, which means this battle. Since then, the most famous battle is the naval battle of Salami Bay. Greece tricked Persia into attacking and defeated the Persian navy. This is a war between Asian countries and European countries. The two sides fought fiercely near the Aegean Sea. It should be the oldest and most complete naval battle recorded in historical materials. Other wars such as ancient Egypt and Phoenicia will not be described in detail. Let's consider the Greek-Persian War as the oldest sea-crossing war.