A symposium or drinking-party was distinct from the dinner which preceded it, and was conducted according to set rules. It generally included entertainment by professional musicians and dancers. Drinking was very formal, at any rate to begin with, and was regulated by the president, who prescribed the proportion of water to be mixed with the wine and the size of the draughts. This is the point of the discussion initiated by Pausanias. The three libations with which dinner ended correspond somewhat to a modern grace, and were offered to Olympian Zeus, the Heroes, and Zeus the Saviour, and followed by a traditional song.