The Madison Avenue entrance to the J.P. Morgan Jr. house, January 27, 1937.

The freestanding Italianate brownstone mansion was built in 1852-3 for Isaac Newton Phelps, whose family’s copper mining fortune funded the construction of three such mansions on Madison Avenue, between 36th and 37th Streets. Isaac Phelps, himself, was a wealthy merchant and banker.

Having purchased the southernmost house in 1882, J.P. Morgan Sr. acquired Phelps’ home at No. 231 and the remaining mansion in between in 1903. Morgan demolished the middle house, using its lot for a private garden, and gave the No. 231 to his son, J.P. Morgan, Jr. In 1928, Morgan Sr.’s house was razed for the construction of the Morgan Library.

When J.P. Morgan Jr. died in 1943, the Lutheran Church acquired the building, setting off a long-running preservation saga. In 1965, the Church signaled its intent to build an office building on the site, which was subsequently declared a New York City Landmark, protecting the property. The Church appealed the ruling successfully, and in 1974, the Landmark status was reversed. However, the Lutherans no longer had the funds to pursue their planned construction. With the mansion’s status uncertain, the Landmarks Preservation Commission re-designated the building that year. This time, there was no appeal.

The Landmark limbo ended in 1988, when the Morgan Library purchased the property, securing its future and tying its legacy to the collection of its most prominent owner. Today, it’s home to the museum offices, store, and cafe.