Jennie Louise Flagler Benedict was the daughter of Henry Flagler. On March 25, 1889, Jennie passed away from childbirth complications while on the way to visit her father. She was traveling by yacht, and died off the coast of South Carolina, aboard her father-in-law's (Commodore Benedict's) yacht the Oneida.
The women in Flagler's life had a profound influence on him and after the shock of his daughter's passing, the guilt he felt led him to change his work habits and lifestyle.
Henry hired renowned architects John M. Carrere and Thomas Hastings to build the Venetian Renaissance Revival-style church in 1890 where Jennie, her daughter Marjorie, Henry Flagler, and his first wife Mary Harkness are laid to rest in the mausoleum.
Upon her death in 1881 in New York, Henry's first wife, Mary Harkness Flagler, was initially interred at Woodlawn in The Bronx, New York. After Henry built the Memorial Presbyterian Church and the attached Flagler Mausoleum, he had Mary's remains moved to be with their daughter there in the new mausoleum. When Henry passed away, he too was interred there along with his family. I believe his son Harry took the plot at Woodlawn for his use since he had moved to New York. Harry and his family are interred there.
After Henry's passing, his third wife, Mary Lily Kenan Flagler, married again. Upon her passing, she was interred at Oakdale Cemetery, Wilmington, NC.
