When Pierpont Morgan died in 1913, he left his vast collections as well as the magnificent library he built next door to his home to his son, J. P. Morgan, Jr., who was known as Jack. The younger Morgan gave many of the works of art to the Metropolitan Museum of Art and the Wadsworth Atheneum, in Hartford, Connecticut. He kept the books, manuscripts, drawings, and prints, among other collections, and formed a public institution to make these collections available.
In 1924, following his mother’s death, Jack Morgan commissioned the Annex, a building containing space for exhibitions and scholarly research on the site of his parents’ home, adjacent to the original Library. He hired the architect Benjamin Wistar Morris to design it. Morris took his cues from the Charles Follen McKim building next door but did not try to compete with McKim’s Renaissance-style palace. A long narrow gallery connected the two buildings, where the modern Clare Eddy Thaw Gallery is today.
The project took four years, and the Morgan opened its doors as a public institution in October 1928.