Livy was born in northeastern Italy. Living from 59 BC - 17 AD), he witnessed the fall of the Republic and establishment of empire. He seems to have devoted his life to the study of history.
In Rome, he won the respect of the emperor Augustus, although Livy had strong Republican sympathies. A major goal of his histories was to contrast the greatness of early Rome with the moral decline he was witnessing in his day. He later mentored the future emperor Claudius in his historical studies.
His work, Ab Urbe Condita (From the Founding of the City), consisted of an amazing 142 books. These were published one or two books a time, and Livy worked on this massive project for the final 46 years of his life.
As the title suggests, the history begins with the founding of Rome and ended in 43 B.C., the year in which Livy died. Many of the books have been lost over the centuries, but his early works (books 1-10, 21-45) survive largely intact.
Oxford Concise Companion to Classical Literature. ed. Howatson and Chilvers. Oxford. New York, 1993.