The ancient Maya civilization developed a complex calendar system based on astronomy. They created a sophisticated system that included two main calendar cycles: the Tzolk'in, a 260-day ritual calendar, and the Haab', a 365-day solar calendar. Their understanding of celestial movements allowed for precise observation of the cycles of the sun, moon, and planets, which played a crucial role in their agricultural practices and rituals. The Maya’s contributions to mathematics and astronomy, such as the concept of zero, were highly advanced for their time and influenced their culture and efforts in timekeeping.