1611 he issued an _Apologia_ or "third part" of the _Satyricon_, in
answer to the attacks of the Jesuits and others who were probably
embittered by the tone of the earlier parts of the satire. A so-called
"fourth part," with the title of _Icon Animorum_, appeared in 1614. James
I. is said to have been attracted by his scholarship, but particulars of
this, or of his life in London generally, are not available. In 1616 he
went to Rome, for some reason unexplained, and there resided till his death
on the 15th of August 1621. He appears to have been on better terms with
the Church and notably with Bellarmine; for in 1617 he issued, from a press
at Cologne, a _Paraenesis ad Sectarios_, an attack on the position of
Protestantism. The literary effort of his closing years was his best-known
work the _Argenis_, completed about a fortnight before his death, which has
been said to have been hastened by poison. The romance was printed in Paris
in the same year.

Barclay's contemporary reputation as a writer was of the highest; by his
strict scholarship and graceful style he has deserved the praise of modern
students. The _Satyricon_, a severe satire on the Jesuits, is modelled on
Petronius and catches his lightness of touch, though it shows little or
nothing of the tone of its model, or of the unhesitating severity and
coarseness of the humanistic satire of Barclay's age. The _Argenis_ is a
long romance, with a monitory purpose on the dangers of political intrigue,
probably suggested to him by his experiences of the league in France, and
by the catholic plot in England after James's accession. The work has been
praised by all parties; and it enjoyed for more than a century after his
death a remarkable popularity. Most of the innumerable editions are
supplied with a key to the characters and names of the story. Thus
Aneroetus is Clement VIII; _Arx non eversa_ is the Tower of London;
Hippophilus and Radirobanes are the names of the king of Spain; Hyanisbe is
Queen Elizabeth; Mergania, by an easy anagram, is Germany; Usinulca, by
another, is Calvin. The book is of historical importance in the development
of 17th century romance, including especially Fenelon's Telemaque. Ben
Jonson appears, from an entry at Stationers' Hall on the 2nd of October
1623, to have intended to make a translation. Barclay's shorter poems, in
two books, were printed in the _Delitiae Poetarum Scotorum_ (Amsterdam,
1637, i. pp. 76-136). In the dedication, to Prin