The Consolation of Philosophy by Boethius

According to Wikipedia: Anicius Manlius Severinus Boëthius,commonly called Boethius (ca. 480–524 or 525 AD) was a philosopher of the early 6th century. He was born in Rome to an ancient and prominent family which included emperors Petronius Maximus and Olybrius and many consuls... Boethius was imprisoned and eventually executed by King Theodoric the Great, who suspected him of conspiring with the Eastern Roman Empire. While jailed, Boethius composed his Consolation of Philosophy, a philosophical treatise on fortune, death, and other issues. The Consolation became one of the most popular and influential works of the Middle Ages.