In "Cyropaedia" (370 BC), Xenophon wrote about the Persian custom of kissing in the lips upon departure while narrating the departure of Cyrus the Great (c. 600 BC) as a boy from his Median kinsmen. According to Herodotus (5th century BC), when two Persians meet, the greeting formula expresses their equal or inequal status. They do not speak; rather, equals kiss each other on the mouth, and in the case where one is a little inferior to the other, the kiss is given on the cheek.