900), alliance with Calakmul frequently was associated with the promise of military support. The fact that Copán, a much more powerful city than Quiriguá, failed to retaliate against its former vassal implies that it feared the military intervention of Calakmul. Calakmul itself was far enough away from Quiriguá that K'ak' Tiliw Chan Yopaat was not afraid of falling directly under its power as a full vassal state, even though it is likely that Calakmul sent warriors to help in the defeat of Copán. The alliance instead seems to have been one of mutual advantage, Calakmul managed to weaken a powerful ally of Tikal while Quiriguá gained its independence.
In 718, the city of Xkuy – an as yet undiscovered site – was attacked and burned by Copán under the leadership of king Uaxaclajuun Ub'aah K'awiil. After the king of Copán was sacrificed in 738, Xkuy seems to have become a loyal vassal of Quiriguá and in 762 K'ak' Tiliw Chan Yopaat supervised the accession of "Sunraiser Jaguar" to the subservient city's throne.
K'ak' Tiliw Chan Yopaat, who had so dramatically changed the destiny of his city, died on 27 July 785. Zoomorph G is his memorial stone and it describes how he was buried 10 days later in the 13 Kawak House, a building that has not been identified. The great king was succeeded by "Sky Xul", a king whose name has not been properly identified. "Sky Xul" became the reigning lord of Quiriguá 78 days after the death of K'ak' Tiliw Chan Yopaat, who is thought to have been his father. His reign lasted from 10 to 15 years and was a period of continued activity. In most of the Maya region cities already were suffering terminal decline, engulfed by the Classic Maya collapse, but in Quiriguá "Sky Xul" dedicated three great zoomorph sculptures and two altars, considered marvels of Maya stoneworking. "Sky Xul" died some time between 795 and 800.
Decline and
