PALENQUE, Mexico (Reuters) -- As Mexico's President Ernesto Zedillo
                  stared across the centuries at an intricate throne -- the seat of power of a
                  once mighty Mayan leader -- he may have spared a thought for the fleeting
                  nature of political power.

                  The stone throne, bearing intricately carved reliefs of three Mayan leaders,
                  was uncovered last July by archaeologists in a temple buried in the jungle in
                  the ancient Mayan city of Palenque.

                  The temple and its long-hidden secrets, which Zedillo visited on Wednesday,
                  could yield vital clues as to what exactly happened between AD 731 and
                  774 -- one of the last periods of stable rule before Palenque's civilisation
                  collapsed in the ninth century.

                  One of the governors who ruled Palenque during those years slipped into
                  oblivion and little is known about his fate.

                  Palenque's pyramids held sway for some 1,200 years over a large swathe of
                  the Mayan world, which in its heyday spread its tentacles from southern
                  Mexico to present day Honduras.

                  Archaeologists have long regarded that 43-year span in the middle of the
                  eighth century as a lost era which has escaped the attention of chroniclers of
                  Palenque's mysterious history.

                  A burial chamber has also been discovered, containing ceramic vases, jade
                  beads and human remains. Uniquely for Palenque, the chamber has mural
                  paintings of Mayan gods.

                  Zedillo praised the beauty of the stone carvings, which mark a high point in
                  Palenque's art, "Apart from their enormous historic value ... we can also see
                  that these pieces have extraordinary artistic value."

                  But what really excites historians and archaeologists are what the reliefs and
                  glyphs can tell them about the governor of Palenque who built the temple,
                  Akul Ahnab III, and the circumstances that led to his ascent to the throne.

                  While modern rulers justify their stay in office by winning elections, Mayan
                  rulers would invoke special links with the gods and dynastic privilege.

                  "It helps us to put some order into this space of time and these inscriptions
                  provide the only record we have," said Arnoldo Gonzalez, an archaeologist
                  who has spent more than a decade sifting through Palenque's treasures.

                  The central panel in the throne depicts Akul Ahnab, who took office in 721
                  AD, when he was 43, already a fairly advanced age in an agriculture-based
                  civilisation where most ordinary mortals lived for barely 40 years.

                  Akul Ahnab's claim to power appears to have been at best tenuous. The last
                  recorded mention of him was in 739 AD when he would have been more
                  than 60 years old.

                  The throne passed from father to son under Palenque's dynastic system but
                  one of Ahnab's immediate predecessors was captured in a war with a
                  nearby community -- throwing the succession into disarray -- and a regent
                  was installed.

                  Anab was the son of a scribe who served in the court of Pakal, the governor
                  who ruled when Palenque was at its zenith.

                  Glyphs suggest Ahnab took power on a date in the Mayan calendar full of
                  significance because it coincided with the day in 3,309 BC when the Mayan
                  gods were deemed to have come into being.

                  "In Palenque, when a leader had a problem of legitimacy he either
                  established a link with the gods or with former rulers," said Alfonso Morales,
                  who heads excavations on behalf of Mexico's National Anthropology and
                  History Institute (INAH).