Xochi­cal­co is an excep­tion­al­ly well-pre­served exam­ple of a for­ti­fied polit­i­cal, reli­gious and com­mer­cial cen­tre from the trou­bled peri­od of 650–900 that fol­lowed the break-up of the great Mesoamer­i­can states such as Teoti­hua­can, Monte Alban, Palenque and Tikal.