Solstices and equinoxes during one year as seen from the Griffith Observatory in Los Angeles (composite image by Mike Kelley on behalf of © Luwian Studies #5036)
Since its founding in 2014, Luwian Studies has explored whether scientific methods can shed light on the cosmological and religious beliefs of the Luwians and Hittites. Central to this research is the rock sanctuary of Yazılıkaya, located near the Hittite capital, Hattuša. The sanctuary is located just outside the city walls of Hattuša and has been a UNESCO World Heritage Site along with the ancient city since 1986.
The site contains over 90 elaborate reliefs of gods and mythical creatures carved into two natural chambers at eye level in almost vertical limestone walls. They form a stunning visual narrative. Since Charles Texier became the first Western European archaeologist to document the sanctuary in 1834, scholars have sought to unravel the meaning behind these reliefs. While their divine nature is evident – many figures bear the Luwian hieroglyphic sign for gods – their deeper significance remains a subject of intense study, adding to the site’s enduring allure.
Yazılıkaya Chamber A main scene (© Luwian Studies #1216)
The Lydians, Phrygians, Mysians and Lycians, which antiquity regarded as branches of one and the same people.
In 2018, archaeologists Eberhard Zangger and Rita Gautschy proved that the numbers in Chamber A of Yazılıkaya are arranged in groups of 12, 30, 5, and 19 – numbers with astronomical significance: 12 times 30 plus 5 equals 365, the number of days in the solar year. Together, these numbers form a lunisolar calendar because they correspond to the celestial cycles: 12 represents the lunar months, 30 the maximum number of days in a lunar month, while the 19 (today 17) female figures on the eastern wall correspond to the solar years and the Metonic cycle – a 19-year scheme that synchronizes the lunar and solar calendars.
This calendar allowed Hittite priests to precisely determine religious festivals and align them with astronomical events and the agricultural cycle. The discovery demonstrates the advanced astronomical knowledge of the Hittites and its close connection to their religious and daily lives.
Further research at the rock sanctuary of Yazılıkaya, now involving astronomer E.C. Krupp and ancient historian Serkan Demirel, suggests that the sanctuary’s figures align with the tripartite cosmos: heaven, earth, and the underworld. Unlike temples in Mesopotamia and Egypt, which expressed cosmic symbolism through man-made architecture, Yazılıkaya uniquely integrates this concept into the natural environment.
Chamber A represents both the earth and the celestial sphere. It features deities associated with the stars, with the central group linked to the circumpolar region of the sky – symbolizing stability and eternal cosmic order. Chamber B, by contrast, is dominated by Nergal, the god of the underworld, embodying death, rebirth, and the cyclical nature of celestial movements and seasonal changes. This naturalized cosmic model portrays a universe inhabited by deities of varying ranks, offering profound insights into how the Hittites perceived and harmonized their spiritual beliefs with the natural world.
The deities on Yazılıkaya’s central panel, led by the supreme storm god Teshub, appear to correspond to the circumpolar stars, which never set and thus symbolize eternal stability. This association aligns with widespread ancient traditions in which the northern sky was seen as the cosmic anchor around which the universe revolved. Similar concepts existed in Egypt, where the pharaoh’s soul was believed to ascend to the “imperishable stars” of the northern celestial sphere.
The orientation of Yazılıkaya’s main reliefs toward this region suggests that the Hittites, too, regarded the circumpolar sky as the domain from which their highest gods communicated with their earthly representative. This interpretation deepens our understanding of Hittite kingship, where the ruler was seen as a mediator between heaven and earth, securing divine favor by aligning his rule with the eternal cycles of the cosmos.
The ground plans of the temple complexes at Hattuša and Yazılıkaya reveal clear references to astronomical parameters. Many temples are aligned with significant celestial points, such as the sunset on the summer solstice. At Yazılıkaya, the first temple building constructed in front of the rock sanctuary shares this alignment, as do certain city gates.
A particularly intriguing feature is an eccentrically placed pedestal in the courtyard of Yazılıkaya’s temple complex. It may have supported a statue of a god, illuminated by natural light only once a year during the summer solstice festival. Witnessing this rare epiphany, participants would then enter Chamber A, where the relief of the Great King was similarly illuminated during the solstice. This alignment symbolically transferred the gods’ magical power to the king, reinforcing his divine mandate and authority as a mediator between the celestial and earthly realms during these sacred festivities.
Yerkapı, the highest architectural feature of Hattuša, is strictly north-facing, as shown in this time-lapse film, with star trails emphasizing the cosmic axis (© Bernd Pröschold on behalf of Luwian Studies #1041)
The artificially erected Chamber 1 in Hattuša opens toward the winter solstice sunset, here in 2018 (© Luwian Studies #1027)
Like many Ancient Near Eastern temples, Yazılıkaya reflects a worldview in which cosmic order was central to both social and spiritual life. Its design embodies the static horizons of the cosmos as well as the cyclical movements of celestial bodies, codifying the passage of time and reinforcing the belief that harmony between heaven and earth was vital to the kingdom’s stability. Yazılıkaya thus stands as a timeless testament to humanity’s enduring quest to understand the cosmos and weave it into the cultural fabric.
The rock sanctuary of Yazılıkaya was not an isolated monument but part of a broader Hittite tradition that integrated celestial knowledge into religious and political life. Recent studies show that the orientation of numerous Hittite temples aligns with significant solar and lunar events, reinforcing the idea that religious ceremonies were timed with celestial cycles. This suggests that the Hittites, like their Mesopotamian and Egyptian counterparts, relied on astronomical observations to structure their calendar and maintain cosmic harmony.
The placement of Yazılıkaya at an elevation of over 1,400 meters above sea level may have been deliberate, offering an unobstructed view of key celestial phenomena. The sanctuary thus functioned not only as a sacred space but also as a center for astronomical observation, reinforcing the king’s divine legitimacy by synchronizing earthly rule with celestial order.
Chamber B of Yazılıkaya, with its depiction of the underworld god Nergal and twelve identical male deities wielding sickle-shaped swords, reflects a fundamental aspect of Hittite cosmology: the cycle of death and rebirth. In Hittite belief, the underworld was not a final destination but a transitional space where celestial cycles continued beyond human perception. This idea resonates with Mesopotamian traditions, where the sun’s nocturnal journey through the underworld ensured the renewal of time. The presence of lion-headed demons guarding the entrance to Chamber B further underscores this threshold between worlds, paralleling Mesopotamian protective spirits that safeguarded liminal spaces. These elements suggest that Yazılıkaya was designed to illustrate not only the visible cosmos but also the unseen forces governing life and death.
The structures and principles identified at Yazılıkaya can now be applied to other monuments and artifacts from the Late Bronze and Early Iron Ages. This has enabled researchers to develop a more cohesive understanding of the worldview of that era, shedding light on previously enigmatic finds and revealing the broader cultural and spiritual framework of the time.
The relief of the Great King Tudhaliya IV in Chamber A of the Hittite rock sanctuary of Yazılıkaya is illuminated by natural sunlight only around the summer solstice (© Luwian Studies #1221)