The ancient Greeks placed a coin, called Charon's toll, in the mouth or hand of a dead person to pay Charon for ferrying the spirit across the River Styx to the Elysian Fields. In some places, it is still traditional to place pennies on the eyes of a dead person prior to burial. While the first toll road has not been identified, Aristotle's Oeconomicus and Pliny's Natural History note land tolls in Asia, while the Sanskrit text The Arthasastra mentions tolls prior to the fourth century B.C. Strabo in Geographies, written at the time of Augustus, reports tolls on the Little Saint Bernard's Pass maintained by the Salassi (a Celtic) tribe. As the Roman Empire declined, the central authority necessary to build and maintain a safe and free (to travelers) road system declined with it, so tolls (not necessarily authorized) became more widespread.