Architect and developer William M. Calder, who helped shape the Park Slope we know today, also found time to serve in the House of Representatives and to become elected to the United States Senate. Calder died on March 3, 1945, and his obituary was carried in the next day's New York Times:
Calder's residence at the time of his death was 551 First Street, on the north side of First Street's "park block", within the current boundaries of the Park Slope Historic District. One notes that Calder chose to reside in a house designed by another architect (P. J. Cullen, according to the historic district's Designation Report), rather than in a residence that he had designed himself.
An election-season profile of William Calder in the New York Times of Oct. 22, 1922 notes that he had become associated with the so-called "Calder House" or two-family house, which proliferated in the "Flatbush section" of the borough. The "Calder House", notes the article, appeals "strongly to beginners in housekeeping, otherwise known as 'newly-weds'." The article also notes that Senator Calder was born on March 3, 1869: