The monasteries also represent an example of a new architectural concept in which open spaces are of renewed importance. The great atria, which are open spaces, surround the entire perimeter of the church (in some cases most of it). Criterion (ii): The considerable influence exercised by the architectural model of the Earliest 16th-Century Monasteries on the Slopes of Popocatepetl, which spread over a very wide area, is incontestable. Criterion (iv): The Earliest 16th-Century Monasteries on the Slopes of Popocatepetl is a group of monasteries selected as being representative of a large total. Protection and management requirementsThe legal protection of the Earliest 16th-Century Monasteries on the Slopes of Popocatepetl involves three different levels of the government: federal, state and municipal.