By: Stephanie Pappas, LiveScience Senior Writer
Published: 06/28/2012 04:22 PM EDT on LiveScience

A newly discovered Mayan text reveals the "end date" for the Mayan calendar, becoming only the second known document to do so. But unlike some modern people, ancient Maya did not expect the world to end on that date, researchers said.

"This text talks about ancient political history rather than prophecy," Marcello Canuto, the director of Tulane University Middle America Research Institute, said in a statement. "This new evidence suggests that the 13 bak'tun date was an important calendrical event that would have been celebrated by the ancient Maya; however, they make no apocalyptic prophecies whatsoever regarding the date."

The Mayan Long Count calendar is divided into bak'tuns, or 144,000-day cycles that begin at the Maya creation date. The winter solstice of 2012 (Dec. 21) is the last day of the 13th bak'tun, marking what the Maya people would have seen as a full cycle of creation.

New Age believers and doomsday types have attributed great meaning to the Dec. 21, 2012 date, with some predicting an apocalypse and others some sort of profound global spiritual event. But only one archaeological reference to the 2012 date had ever been found, as an inscription on a monument dating back to around A.D. 669 in Tortuguero, Mexico. [End of the World? Top Doomsday Fears]

Now, researchers exploring the Mayan ruins of La Corona in Guatemala have unearthed a second reference. On a stairway block carved with hieroglyphs, archaeologists found a commemoration of a visit by Yuknoom Yich'aak K'ahk' of Calakmul, the most powerful Mayan ruler in his day. The king, also known as Jaguar Paw, suffered a terrible defeat in battle by the Kingdom of Tikal in 695.

Historians have long assumed that Jaguar Paw died or was captured in this battle. But the carvings proved them wrong. In fact, the king visited La Corona in A.D. 696, probably trying to shore up loyalty among his subjects in the wake of his defeat four years earlier. [See images of the carvings]

As part of this publicity tour, the king was calling himself the "13 k'atun lord," the carvings reveal. K'atuns are another unit of the Maya calendar, corresponding to 7,200 days or nearly 20 years. Jaguar Paw had presided over the ending of the 13th of these k'atuns in A.D. 692.

That's where the 2012 calendar end date comes in. In an effort to tie himself and his reign to the future, the king linked his reign with another 13th cycle — the 13th bak'tun of Dec. 21, 2012.

"What this text shows us is that in times of crisis, the ancient Maya used their calendar to promote continuity and stability rather than predict apocalypse," Canuto said.

La Corona was the site of much looting and has only been explored by modern archaeologists for about 15 years. Canuto and his dig co-director Tomas Barrientos Q. of the Universidad del Valle de Guatemala announced the discovery of the new calendar text Thursday (June 28) at the National Palace in Guatemala.

The researchers first uncovered the carved stone steps in 2010 near a building heavily damaged by looters. The robbers had missed this set of 12 steps, however, providing a rare example of stones still in their original places. The researchers found another 10 stones from the staircase that had been moved but then discarded by looters. In total, these 22 stones boast 264 hieroglyphs tracing the political history of La Corona, making them the longest known ancient Maya text in Guatemala.

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Check out these photos from an excavation of an ancient Mayan structure in Guatemala's Peten region.
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  • "Younger Brother Obsidian," as labeled on the north wall of the Maya city's house by an unknown hand, was painted in the 9th century A.D. Archaeologist William Saturno of Boston University excavates the house in the ruins of the Maya city of Xultún. Younger Brother Obsidian may have been the town scribe. Excavation and preservation of the site were supported by the National Geographic Society. Photo by Tyrone Turner © 2012 National Geographic

  • Trees grow atop a newly discovered mound over a house built by the ancient Maya that contains the rendering of an ancient figure, possibly the town scribe. The house sits at the edge of the ancient site of Xultún in Guatemala, a city that once housed tens of thousands of people. Excavation and preservation of the site were supported by the National Geographic Society. Photo by Tyrone Turner © 2012 National Geographic

  • Three male figures, seated and painted in black. The men, wearing only white loincloths and medallions around their necks and a head dress bearing another medallion and a single feather, were uncovered on the ruined house's west wall. The painting recreates the design and colors of the original Maya mural. Excavation and preservation of the site were supported by the National Geographic Society. Painting by Heather Hurst

  • A Maya king, seated and wearing an elaborate head dress of blue feathers, adorns the north wall of the ruined house discovered at the Maya site of Xultún. An attendant, at right, leans out from behind the king's head dress. The painting by artist Heather Hurst recreates the design and colors of the original Maya artwork at the site. The excavation and preservation of the site were supported by the National Geographic Society. Painting by Heather Hurst

  • A vibrant orange figure, kneeling in front of the king on the ruined house's north wall, is labeled "Younger Brother Obsidian," a curious title seldom seen in Maya text. The man is holding a writing instrument, which may indicate he was a scribe. The painting recreates the design and colors of the figure in the original Maya mural. Excavation and preservation of the site were supported by the National Geographic Society. Painting by Heather Hurst

  • Four long numbers on the north wall of the ruined house relate to the Maya calendar and computations about the moon, sun and possibly Venus and Mars; the dates may stretch some 7,000 years into the future. These are the first calculations Maya archaeologists have found that seem to tabulate all of these cycles in this way. Although they all involve common multiples of key calendrical and astronomical cycles, the exact significance of these particular spans of time is not known. Illustration by William Saturno and David Stuart © 2012 National Geographic

  • The painted figure of a man -- possibly a scribe who once lived in the house built by the ancient Maya -- is illuminated through a doorway to the dwelling, in northeastern Guatemala. The structure represents the first Maya house found to contain artwork on its walls. The research is supported by the National Geographic Society. Photo by Tyrone Turner © 2012 National Geographic

  • Conservator Angelyn Bass cleans and stabilizes the surface of a wall of a Maya house that dates to the 9th century A.D. The figure of a man who may have been the town scribe appears on the wall to her left. Excavation and preservation of the site were supported by the National Geographic Society. Photo by Tyrone Turner © 2012 National Geographic

  • Never-before-seen artwork -- the first to be found on walls of a Maya house -- adorn the dwelling in the ruined city of Xultún. The figure at left is one of three men on the house's west wall who are painted in black and wear identical costumes. Excavation and preservation of the site were supported by the National Geographic Society. Photo by Tyrone Turner © 2012 National Geographic

  • Archaeologist William Saturno of Boston University carefully uncovers art and writings left by the Maya some 1,200 years ago. The art and other symbols on the walls may have been records kept by a scribe, Saturno theorizes. Saturno's excavation and documentation of the house were supported by the National Geographic Society. Photo by Tyrone Turner © 2012 National Geographic