 Copán was firmly allied with Tikal and Calakmul used its alliance with Quiriguá to undermine Tikal's key ally in the south.Although the exact details are unknown, in April 738 K'ak' Tiliw Chan Yopaat captured Uaxaclajuun Ub'aah K'awiil and burned two of Copán's patron deities.Six days later Uaxaclajuun Ub'aah K'awiil was decapitated in Quiriguá.