The "Treatise on Taxation", preserved in the Biblioteca Marciana in Venice, distinguishes between three types of rural settlements, the "chorion" (Greek: χωρίον) or village, the "agridion" (Greek: αγρίδιον) or hamlet, and the "proasteion" (Greek: προάστειον) or estate. According to a 14th-century survey of the village of Aphetos, donated to the monastery of Chilandar, the average size of a landholding is only 3.5 modioi (0.08 ha). Taxes placed on rural populations included the "kapnikon" (Greek: καπνικόν) or hearth tax, the "synone" (Greek: συνονή) or cash payment frequently affiliated with the "kapnikon", the "ennomion" (Greek: εννόμιον) or pasture tax, and the "aerikon" (Greek: αέρικον, meaning "of the air") which depended on the village's population and ranged between 4 and 20 gold coins annually.