His next official appointment opened to him a new field for thought. In B. C. 63 he obtained the office of Pontifex Maximus, and examined so diligently into the history and nature of the Roman belief in augury, of which he was the official guardian, that his investigations were published in a work consisting of at least sixteen books (_Libri Auspiciorum_.[916]) In order to fit himself for discharging the duties of his office he studied astronomy, and even wrote a treatise on that science,[917] entitled “_de Astris_”, and a poem somewhat resembling the Phenomena of Aratus. His knowledge of this science enabled him, with the aid of the Alexandrian astronomers, to carry into effect some years[918] afterwards the reformation of the calendar. The works above mentioned are philosophically and scientifically valueless, but curious and interesting; but we have now to view Cæsar in that capacity which was the foundation of his literary reputation. He obtained the province of Hispania Ulterior;[919] and at this post his career as a military commander began. As had been the case during his previous career, so now the almost incessant demands on his thoughts and time did not divert him from literary pursuits, but determined the channel in which his tastes should seek satisfaction, and furnished the subject for his pen. He had evidently an ardent love for literature for its own sake. It was not the paltry ambition of showing that he could achieve success, and, even superiority, in every thing which he chose to undertake, although his versatility of talent was such as to encourage him to expect success, but a real attachment to literary employment. Hence whatever leisure his duties as a military commander permitted him to enjoy was devoted, as to a labour of love, to the composition of his Memoirs or Commentaries of the Gallic and Civil Wars. His comprehensive and liberal mind was also convinced of the embarrassing technicalities which impeded the administration of the Roman law. Its interpretation was confined to a few who had studied its pedantic mysteries; and the laws which regulated the _dies fasti_ and _nefasti_ had originally placed its administration in the hands of the priests and patricians. Appius Claudius had already commenced the work of demolishing the fences which to the people at large were impregnable; and Cæsar entertained the grand design of reducing its principles and practice to a regular code.[920] His views he imbodied in a treatise,[921] which, as is often the case with pamphlets, perished when the object ceased to exist for which it was intended.