[3] W.A.C Ryan entered the Union Army at the onset of the American Civil War as a member of the New York Volunteers, serving in the 132nd Infantry Regiment and later achieving the rank of captain.

[6] Shortly after, Ryan authored articles for New York newspapers that included false statements and a disparaging message directed at the surgeon overseeing Foster General Hospital, where he was receiving treatment.

William A.C. Ryan, in 1869, worked for the Cuban Junta in New York, focusing on acquiring military supplies and coordinating expeditions for the insurrection.

[9][10] Arrest warrants were issued for the individuals, and Ryan was apprehended shortly thereafter, being held in the Ludlow Street Jail before his release on bail.

On June 6, 1872, a failed expedition led by General Julio Grave de Peralta and Colonel William A.C. Ryan embarked from New York aboard the filibustering steamer known as the "Fannie.

[18] A joint resolution approved in 1882 allowed William Ryan's mother Eliza Dunne to receive a part of the indemnity funds from the Government of Spain.