Douglas Harper's Etymology Dictionary
Petrarchan
1827 (Keats uses Petrarchal, 1818), from Francesco Petrarch (Italian Petrarca) the poet (1304-1374).
Wikipedia
Usage examples of "petrarchan".
It also represents, as Belli tells Cardinal Fabiani, the octave of the rhyme scheme of a petrarchan sonnet.
The fourth was a perfectly good Petrarchan sonnet reviling the current administration and the party of which Len was an assenting member.