In 1555 Vesalius was the first to diagnose an aneurysm of the thoracic and abdominal aorta in a living person. Vesalius wrote this consilium to Achilles Pirmin Gasser on July 18, 1557; it was not published until more than 100 years later. The consilium was in response to a notice from Gasser regarding the death of the Augsburg patrician, Leonard Welser, whom Vesalius had seen as a patient in 1555. Ever since a ride on horseback, Welser had suffered severe and constant pain. Upon examination Vesalius discovered a pulsating tumor in the region of the vertebrae, and immediatedly diagosed a fatal aneurysm of the aorta. After suffering with this disease for two years, Welser resorted to a quack, who, it was thought, contributed to his demise. Gasser's autopsy report confirmed Vesalius's original diagnosis. Regarding the consilium, in Andreas Vesalius of Brussels (1964) C.D. O'Malley translated Rumler's comments as follows: "When in 1557 that noble gentleman Leonard Welser finally died from an internal aneurism from which he had long suffered its various symptoms, on 25 June Adolph Occo, father and son, Ambrose Jung, and Lucas Stengel, physicians of Augsburg, dissected the body in order to find the cause of death, and Achilles Gasser, my maternal grandfather, sent their findings to Vesalius." Vesalius's consilium and much other material collected and preserved by Rumler seems to have been first published by Welsch, as part of a larger collection. O'Malley also translated Gasser's report to Vesalius on pp. 406-07, and translated Vesalius's consilium on pp. 395-96. Digital facsimile of the 1667 edition from Google Books at this link.