This diploma thesis is focused on the question how the Maya from Tikal celebrated ends of the katun cycles of their calendar during the Classic period. To answer this question the tesis brings the analysis of all Tikal's katun period-ending steale and altars. The accent is put on katun period-ending rituals. This thesis is also concerned with twin-pyramid complexes which were developed at Tikal to host katun-ending commemoration. Keywords Pre-Columbian America, Mesoamerica, the Maya, the Maya calendar, katuns, rituals, stelae.