His chief works in these ten years were, "A Tour on the Prairies," "Recollections of Abbotsford and Newstead Abbey," "The Legends of the Conquest of Spain," "Astoria" (the heavy part of the work of it was done by his nephew Pierre), "Captain Bonneville," and a number of graceful occasional papers, collected afterwards under the title of "Wolfert's Roost." Two other books may properly be mentioned here, although they did not appear until after his return from his absence of four years and a half at the court of Madrid; these are the "Biography of Goldsmith" and "Mahomet and his Successors." At the age of sixty-six, he laid aside the "Life of Washington," on which he was engaged, and rapidly "threw off" these two books. The "Goldsmith" was enlarged from a sketch he had made twenty-five years before. It is an exquisite, sympathetic piece of work, without pretension or any subtle verbal analysis, but on the whole an excellent interpretation of the character. Author and subject had much in common: Irving had at least a kindly sympathy for the vagabondish inclinations of his predecessor, and with his humorous and cheerful regard of the world; perhaps it is significant of a deeper unity in character that both, at times, fancied they could please an intolerant world by attempting to play the flute. The "Mahomet" is a popular narrative, which throws no new light on the subject; it is pervaded by the author's charm of style and equity of judgment, but it lacks the virility of Gibbon's masterly picture of the Arabian prophet and the Saracenic onset.