He was born in Pont-à-Mousson, Lorraine, France, where his father, William Barclay, held the chair of civil law. His mother was a Frenchwoman. The Jesuits endeavored to induce him to join their order.
But his father refused to give his consent and took him to England in 1603.
While there, at the age of nineteen, he wrote a commentary on the Thebais of Statius. Barclay had persistently maintained his Scottish nationality in his French surroundings, and probably found in James VI and I"s accession an opportunity which he would not let slip. In early 1604 John Barclay presented James with a Latin poem, "Kalendae Januariae", and afterward dedicated to him the first part of his Euphormionis Satyricon (Euphormionis Lusinini Satyricon) against the Jesuits.
He returned to France by 1605, when a second edition of that book appeared in Paris, having spent some time in Angers.
He was the husband of a Frenchwoman, Louise Debonaire. In 1607 the second part of the Satyricon appeared in Paris.
In 1616 he went to Rome and resided there until his death on 15 August 1621, aged 39. To the Catholic Barclay, this was unacceptable.
In addition he may have been seeking a more generous patron that the somewhat parsimonious King James.
In fact Barclay received a pension of some 150 pounds from the Pope. He wrote his major novel, Argenis, in Rome and, according to his contemporaries, indulged in gardening. One son became bishop of Toul in France and survived until 1673.
