On the wonderful Donegal Heritage site there is a fascinating article about an early modern doctor to Hugh O’Donnell, amongst others.
AMONG the few physicians of the seventeenth century whose names have been preserved from the stream of oblivion, is Nial O’Glacan of Donegal. Forgotten to-day, in his time he was one of the most distinguished members of the medical profession in Spain, France, and Italy, where for many years he had a long and distinguished career. Born in Donegal in the latter half of the sixteenth century, it is probable that he received the rudiments of his medical education from one of the families of hereditary physicians which at that time were attached to the Irish chieftains.
Later we read:
Early in life he left Ireland, and settled in Spain as early as 1602. This latter fact is inferred from his statement that he treated the great Hugh O’Donnell, Lord of Tirconnell, with a special poultice for a “venereo bubo” in the royal palace of the King of Spain. It is known that Hugh O’Donnell died at Simancas on 10th September, 1602, after an illness of fourteen days