He was then not yet thirty-nine years old--B.C.

68--and during that year and the next seven were written eleven letters, all to Atticus.

Those to his other friends--Ad Familiares, as we have been accustomed to call them; Ad Diversos, they are commonly called now--began only with the close of his consular year.
How it has come to pass that there have been preserved only those which were written after a period of life at which most men cease to be free correspondents, cannot be said with certainty.

It has probably been occasioned by the fact that he caused his letters to be preserved as soon as he himself perceived how great would be their value.

Of the nature of their value it is hardly possible to speak too highly.