Some minds corrode and grow inactive under the loss of personal liberty; others grow morbid and irritable; but it is the nature of the poet to become tender and imaginitive in the loneliness of confinement. He banquets upon the honey of his own thoughts, and, like the captive bird, pours forth his soul in melody.

The letters brought Irving some early fame and moderate notoriety. His portrait appeared on the bank's notes and contributed to their wide appeal. He made his literary debut in 1802 with a series of observational letters to the Morning Chronicle written under the pseudonym Jonathan Oldstyle.

His historical works include biographies of George Washington Oliver Goldsmith and Muhammad and several histories of 15th-century Spain dealing with subjects such as Christopher Columbus the Moors and the Alhambra. He continued to publish regularly—and almost always successfully—throughout his life and completed a five-volume biography of George Washington just eight months before his death at age 76 in Tarrytown New York.