Tovar asserts that his works were prepared with the original information of Aztec informants from Tula; however, historians argue that he also extensively utilized the works of Diego Durán, given the undeniable parallels between both. Many scholars believe that, while Tovar may have drawn from Durán, both of them, along with Tezozomoc, based their works on an earlier Nahuatl source (now lost), that is presumed to have been compiled by one or more Aztec historians sometime shortly after the conquest.
Tovar claims his works were based on Aztec informants from Tula; however, historians contend that he also extensively relied on Diego Durán's work, given the evident similarities between both. Many scholars believe that while Tovar may have borrowed from Durán, both of them, along with Tezozomoc, based their works on an earlier Nahuatl source (now lost), which is presumed to have been compiled by one or more Aztec historians shortly after the conquest.