His younger brother, Charles Edward Fagan, later became the secretary of the Natural History Department at the British Museum.

[4] In 1860, he was sent to England by a Queen's Messenger and was taken care of by Sir Anthony Panizzi, a friend of his father's who he would later write a biography on.

[8] In 1893, John Singer Sargent painted a 30.25x25.125 inch oil on canvas portrait of Fagan, which was sold in 2020 at Doyle's for $118, 750[1][9] In his lifetime he wrote 92 articles for the original 1985-1900 Dictionary of National Biography.

The Art of Michel' Angelo Buonarroti as Illustrated by the Various Collections in the British Museum (1883) Collectors' Marks (1183) A Catalogue Raisonné of the Engraved Works of William Woollett (1885) 1836-1886.

The Reform Club: Its Founders and Architect (1887) A Descriptive Catalogue of the Engraved Works of William Faithorne (1888) An easy walk through the British museum, or, How to see it in a few hours (1891) Vita di Michelangelo Buonarroti.