Boethius' most popular work is The Consolation of Philosophy, which he wrote in 524 AD while in prison, or possibly under house arrest, awaiting execution on charges of treason and black magic. He had been a philosopher, translating works of Aristotle and technical works on music and mathematics into Latin. He was consul in 510 under King Theoderic, the Gothic king of Italy, eventually reaching the post of Master of Offices (roughly, head of the civil service) and was so well thought of that both his sons became consul in the same year, 522. We do not know exactly what caused his fall from favour, but it may have had something to do with Theoderic's annoyance at the policies of Justin, the Emperor in Constantinople, who was persecuting Theoderic's fellow Arianists. Boethius himself claims in The Consolation of Philosophy that it was due to enmity he had aroused in corrupt court officials by his own upright behaviour. Not that the two explanations are incompatible, of course.
In the 9th century, King Alfred the Great of England chose The Consolation of Philosophy as one of the six books it was important for everyone to know and translated it into Old English, although his translation incorporates what we would now put as historical background and explanatory notes into the text. Chaucer also translated it in the 1380s, and another royal translation was produced by Elizabeth I in 1593. Gibbon, in his account of Boethius' life and writings calls Boethius "...the last of the Romans whom Cato or Tully could have acknowledged for their countryman" and describes The Consolation of Philosophy as "...a golden volume not unworthy of the leisure of Plato or Tully, but which claims incomparable merit from the barbarism of the times and the situation of the author." C. S. Lewis counted it as one of the top ten books which had most influenced him.
The introduction to this translation into modern English of King Alfred's translation gives samples of translations into English of The Consolation of Philosophy through the ages. Chaucer's translation is online, but as far as I can see Elizabeth I's is not. J. J. O'Donnell has put the Latin text online with notes for those learning Latin, together with W. V. Cooper's 1902 translation. Oxford World's Classics has a 1999 print translation by P. G. Walsh, which, alas, did not get a very good review from the Bryn Mawr Classical Review, mainly I think because the review was written from the viewpoint of the Boethius specialist and focuses on points which would not bother the general reader.
For more information about Boethius' life, see Smith's Dictionary of Greek and Roman Biography and Mythology. The Stanford Encylcopedia of Philosophy has an entry on Boethius as a philosopher, which covers his other works as well as The Consolation of Philosophy and also discusses his influence on mediaeval philosophy.
