[2] According to his sister Harriet Martine Dean, his interest in armour began at age six, when he "spent hours examining a helmet"[3] while visiting the collection of the estate of the late Carlton Gates in Yonkers (d. 1869),[4] a family acquaintance, whose holdings included Asian and Medieval arms and weaponry.

[citation needed] From the 1880s to the early 1900s, his scientific research allowed him to travel to Europe, Russia, Alaska, Japan, and the Pacific coast of the United States.

[10]: n12  His work guided and informed helmet development in the US, and possibly in other countries, at least until the 1980s,[11] although his preferred design was rejected in 1918[10]: 216  and c. 1937,[11] as its resemblance to the German Stahlhelm was considered too close.

[14] After undergoing surgery, he unexpectedly died on December 6, 1928, in Battle Creek, Michigan,[15] missing, only the day before his death, the opening of the "Hall of Fishes", his crowning work at the American Museum of Natural History.

[citation needed] In 2012, the Metropolitan Museum of Art celebrated the centennial of the founding of its Armory collection, and organized the special exhibition Bashford Dean and the Creation of the Arms and Armor Department.