Tlatelolco. It appears that the master tlacuilo drew each set of specific year glyphs (Reed, Flint, House, Rabbit) in one session. This is alluded to by consistencies in form and inconsistencies in color by set. Once these were painted, he added the corresponding years in the Julian calendar, which in their forms resemble the glosses added to the codex later. The first instances of work by the apprentice tlacuilo are found on folio 6v, as there appear houses shaded as per his method. He takes over completely until folio 12r, when the Mexica arrive at Tenochtitlan. History It is not known when the manuscript was created, or whether it was first painted and then bound, or vice versa. Historian María Castañeda de la Paz has proposed the second half of the 16th century as the window of time in which Codex Azcatitlan was authored. The writing of the glosses in Nahuatl suggests a date in the last third of the sixteenth century, but the glosses may not be contemporary with the drawings, since the glossarist did not always understand them correctly. At some point it belonged to the Milanese nobleman Lorenzo Boturini Benaduci (1702–1755), who mentions it in his Idea de una nueva historia general de la América septentrional. Later it was part of the collections of and of Eugène Goupil in France. At the latter's death in 1898, it was donated to the Bibliothèque Nationale. Of the twenty-eight original leaves (21 by 28 centimeters), in European paper, three are lost (between pp. 8–9, 44–45, and 46–47). In 1995, the FNL collaborated with the Society of the Americas to provide a publicly available color copy of the codex. The first historian to write a detailed study of the Azcatitlan Codex was Robert H. Barlow in the mid-20th century. Barlow proposed the idea that the manuscript was produced by two authors and that the senior among them produced its beginning and then the Imperial and post-Conquest history. A decade later, Donald Robertson challenged the proposition that the senior tlacuiloque produced the colonial history segments by himself. Content Codex Azcatitlan is divided into four sections, but records in one narrative the history of the Mexica people from their migration from Aztlán to about 1527, just after the death of Cuauhtémoc. The first portion of the codex is an annal of the Mexica migration from Aztlán that asserts the role of the Tlatelolca