Long before the
Arabs had awakened to an appreciation of Greek Philosophy, he had introduced Aristotle to his countrymen. He was the first
Christian writer to essay the task of compiling for his co-religionists a summa of universal knowledge, in the form of his most important work, the
Etymologiae (taking its title from the method he used in the transcription of his era's knowledge). It is also known by classicists as the
Origines (the standard abbreviation being
Orig.). This
encyclopedia — the first known to be compiled in medieval civilization —
epitomized all learning, ancient as well as modern, forming a huge compilation of 448 chapters in 20 volumes. In it many fragments of classical learning are preserved which otherwise would have been hopelessly lost but, on the other hand, some of these fragments were lost in the first place because Isidore’s work was so highly regarded that it superseded the use of many individual works of the classics themselves, which were not recopied and have therefore been lost.
The fame of this work imparted a new impetus to encyclopedic writing, which bore abundant fruit in the subsequent centuries of the
Middle Ages. It was the most popular compendium in
medieval libraries. It was printed in at least 10 editions between
1470 and
1530, showing Isidore's continued popularity in the
Renaissance. Until the twelfth century brought translations from Arabic sources, Isidore transmitted what western Europeans remembered of the works of
Aristotle and other Greeks, although he understood only a limited amount of Greek. The
Etymologiae was much copied, particularly into medieval
bestiaries.