His principal work, _Guerra de Chile, causas de su duración, medios para su fin_, was completed in 1641, and published in Madrid in 1647. Its title suggests that the author proposed to treat his theme philosophically, and thus initiate a departure from the chronicle-like writings of his predecessors. Medina finds in the book certain observations that reveal an elevated spirit, a judicial character, judgments on men and affairs, and views more or less developed concerning military operations, described from year to year from the beginning of Lazo de la Vega’s administration to the arrival of his successor.[112] In spite of its title, the characteristics of a chronicle are thus seen to be distinctive features of some part of the work, and, like most of the chronicles of the colonies, it fails to maintain a just perspective of the subject, extensive accounts being sometimes given of unimportant events, while events of greater importance suffer comparative neglect. Still Tesillo is not merely a writer of chronicles; he set forth the causes of movements, reasons for the continuation of the war, the interests of the two belligerents, their conflicts, their methods of warfare, the marching of the troops, the astuteness of the Indians, and all this is done with striking impartiality.[113] CHAPTER X WRITERS OF PERU AND NEW GRANADA, 1600-1650. I. _Juan Bautista Aguilar._ II. _Francisco Vásquez and Toribio de Ortiguera._ III. _Cristóbal de Acuña._ IV. _Diego de Torres Bollo._ V. _Antonio de la Calancha._ VI. _Bernabé Cobo._ VII. _Alonso Mesía Venegas._ VIII. _Pedro Simón._ IX. _Rodríguez Fresle and Alonso Garzón de Tahuste._ X. _Pedro Fernández de Quiros, Gobeo de Victoria, and Fernando Montesinos._ I [Sidenote: Peruvian topics] [Sidenote: Aguilar defender of the Indians] [Sidenote: _Restauración y reparo del Perú_]