The Vesalius family originally was named Witing, (_Witting_, _Wytinck_, _Wytings_, according to various authorities) and adopted the name Wesalius from the town of Wesel, (_Wesele_, _Vesel_), in the Duchy of Cleves, which the family claimed as their native place. The three weasels (_Flemish_—“Wesel”), found in the Vesalian coat of arms, testify to this origin. It may be said with truth that medical learning ran in the blood of the Vesalius family. Andreas’s great-great-grandfather, Peter Wesalius, wrote a treatise on some of the works of Avicenna and at great cost restored the manuscripts of several medical authors. Peter’s son, John Wesalius, held the responsible position of physician to Mary of Burgundy, the first wife of Maximilian the First; in his old age John taught medicine in the University of Louvain. From that time the Vesalius family was closely associated with the Austro-Burgundian dynasty. Eberhard, son of John Wesalius, served as physician to Mary of Burgundy; he died before attaining his thirty-sixth year, and was long survived by his father. Eberhard, who was the grandfather of Andreas, wrote commentaries upon the books of Rhazes and on the _Aphorisms_ of Hippocrates. He was also noted as a mathematician. Eberhard’s son Andreas, the father of the anatomist, was apothecary to Charles the Fifth and to Margaret of Austria. He accompanied the great Emperor upon his numerous journeys and military expeditions. In 1538 he presented Andreas’s first anatomical plates to the Emperor, and thus opened the way to the court to his son. The father remained in the imperial service until the day of his death, which occurred in 1546. Andreas’s mother, Isabella Crabbe, exercised a great influence upon the youth whom she believed to be destined to accomplish great things. She it was who preserved the manuscripts and books of the Vesalian ancestors. Isabella happily lived long enough to see the _Fabrica_, to witness the intellectual triumph of her son, and to know of his activity at the Spanish court. [Illustration: THE OLD UNIVERSITY OF LOUVAIN (Erected early in the Fourteenth Century. The New Building dates from 1680)]