deteriorate around 800 AD. Archeologists have determined that the city of Wari was dramatically depopulated by 1000 AD, although it continued to be occupied by a small number of descendant groups. Buildings in Wari and in other government centers had doorways that were deliberately blocked up, as if the Wari intended to return, someday when the rains returned. By the time this happened, though, the Wari had faded from history. In the meantime, the dwindling residents of the Wari cities ceased all major construction. Archaeological evidence shows significant levels of interpersonal violence, suggesting that warfare and raiding increased amongst rival groups upon the collapse of the Wari state structure. With the collapse of the Wari, the Late Intermediate Period is said to begin. Government Little is known about the details of the Wari administrative structure, as they did not appear to use a form of written record. Instead, they used a tool called khipu, or "knot record." Despite being most widely known for its use in Inca accounting, many scholars believe that the earliest use of it as a recording tool happened in Wari. Archaeologists, however, still rely on homogeneous administrative architecture and evidence of significant social stratification to help better understand the complex sociopolitical hierarchy of Wari. The discovery in early 2013 of an undisturbed royal tomb, El Castillo de Huarmey, offers new insight into the social and political influence of the Wari during this period. The variety and extent of the burial items accompanying the three royal women indicate a culture with significant material wealth and the power to dominate a significant part of northern coastal Peru for many decades. Another example of burials helping to establish social stratification is in the city of Conchopata where the remains of more than 200 individuals have been found. This city is located about 10 km from the capital city. Prior to its excavation, the city was believed to be that of potters, but the burials studied instead showed that there were servants, middle-class, elite, and even perhaps low kings or governors occupying the city. Further investigations on a random selection of the burials from the site have shown that 26 percent of both male and female adult crania studied had at least one posterior wound, while only females had been subject to anterior wounds. The different levels of violence based on sex is evidence of some type of systematic hierarchy.