H. H. Richardson won the commission in 1872 and gave America a style — Richardsonian Romanesque — with this building. The problem was the ground: Back Bay is filled tidal marsh, so the church stands on 4,500 wooden piles driven into the muck, kept sound only by staying permanently underwater. The water table is monitored to this day. John La Farge did the interior and contributed important windows. Phillips Brooks, who preached here, wrote "O Little Town of Bethlehem."
Source: Trinity Church in the City of Boston, institutional history and art-and-architecture materials; Boston Groundwater Trust, groundwater monitoring and wooden-pile foundation information; Boston Public Library, Back Bay historical collections; The Episcopal Church, An Episcopal Dictionary of the Church, entry on Phillips Brooks