The historical importance of the Artemision of Amarynthos mainly derives from the chapter that Strabo dedicated to the island of Euboea in the tenth book of his Geography (X 1, 1-13). The sanctuary hosted important public documents, among which a law regulating the annual procession from Eretria to Amarynthos. This ceremony took the form of a military parade composed of 3,000 heavily-armed warriors (hoplitai), 600 cavalrymen (hippeis), and 60 war chariots (harmata). These contingents may be related to an underlying, sophisticated political structure, perhaps linked in some way to the distribution of the Eretrian civic body into six tribes (phylai) starting c. 500 BCE (roughly at the time Athens instituted its ten tribes). Possibly, each tribe provided 500 infantrymen, 100 cavalrymen, and 10 war chariots. A second document recorded by Strabo is the military agreement between the rival cities of Chalkis and Eretria, supposedly banning the use of missiles, a treaty that has most often been associated with the semi-mythical Lelantine War.