The king not only took a leading part in ritual, but ritual is likely to have focused on his office as well. The erection of stelae showing the king and dedicated to the day 'King' ("Ahaw"), which concluded intervals of five 360-day years, constituted a royal ritual by itself. It appears to implicate the king as the divine lord of his own day. Inversely, at San Bartolo, the divine hero of the day 'King', Hunahpu, substitutes for the real king. Setting up a stela may additionally have involved the notion of the king as a protective 'tree of life'. Moreover, in the Classic period, the king is commonly depicted holding a cosmic serpent from whose jaws deities (often those of rain, lightning and fire) emerge; the king's raising and balancing of this serpent, accompanied by his 'conjuring' of the emerging deities, may well have been expressed and supported by ritual.