Isaac Newton Spiegelberg was born in 1859. His family were wholesale clothing merchants who had done well during the Civil War. Although born in the USA he was educated in Germany. Trained as an engineer, he worked for a while on Switzerland’s St. Gotthard Railway. He eventually returned to the US, where he worked on the Atlantic & Pacific Railroad, mostly in Oklahoma. In 1884 he moved away from engineering and took up brokerage with the firm of J & W Seligman. .
In 1909, he built a large (forty-nine room) mansion in the then popular Tudor Revival style on around twenty acres off Sleepy Hollow Road in Briarcliff Manor. He named it “Miramont Court” (Spiegel-mirror, Berg-Mountain).
