Who collected James Boswell’s manuscripts from Malahide Castle?

The American collector Ralph Heyward Isham was responsible for collecting the manuscripts of James Boswell from Malahide Castle.

Beginning in 1927, Isham sought out the papers from the 6th Baron Talbot de Malahide, Boswell’s great-great-grandson. Over the course of more than 20 years, Isham uncovered a vast collection of Boswell’s journals, letters, and other documents hidden in attics and various locations at the castle. He eventually sold the bulk of this collection to Yale University in 1949, where scholars like Frederick A. Pottle began the systematic task of editing and publishing the papers.12