 After this, Copán became one of the more powerful Maya city states and was a regional power in the southern Maya region.However, it suffered a catastrophic defeat at the hands of its former vassal state Quirigua in 738, when the long-ruling king Uaxaclajuun Ub'aah K'awiil was captured and beheaded by Quirigua's ruler K'ak' Tiliw Chan Yopaat (Cauac Sky).Although this was a major setback, Copán's rulers began to build monumental structures again within a few decades.