The "Royal Dublin Fusiliers," or "Royal Dublins," were an Irish infantry regiment of the British army from 1881 until the founding of the Irish Free State in 1922. Molly Bloom's father, identified in Oxen of the Sun as "a gallant major" and in Ithaca as "Major Brian Cooper Tweedy, Royal Dublin Fusiliers" (though he may have been only a sergeant-major), served in this regiment in the 2nd Battalion stationed in Gibraltar. After his time, the regiment sent both of its regular battalions to South Africa to fight in the Second Boer War from 1899 to 1902.
In Proteus, Stephen imagines a gypsy woman's companion selling her body to "two Royal Dublins" in Blackpitts, and this association with prostitution continues in Lotus Eaters when Bloom scans the troops in a recruiting poster looking for the regiment that Molly's father served in: "Where's old Tweedy's regiment? Castoff soldier. There: bearskin cap and hackle plume. No, he's a grenadier. Pointed cuffs. There he is: royal Dublin fusiliers. Redcoats. Too showy. That must be why the women go after them. Uniform. Easier to enlist and drill. Maud Gonne's letter about taking them off O'Connell street at night: disgrace to our Irish capital. Griffith's paper is on the same tack now: an army rotten with venereal disease."
When he is accosted by two policemen in Circe, however, Bloom leaps to associate himself with the troops: "My wife, I am the daughter of a most distinguished commander, a gallant upstanding gentleman, what do you call him, Majorgeneral Brian Tweedy, one of Britain's fighting men who helped to win our battles. Got his majority for the heroic defence of Rorke's Drift." Now the major, perhaps already glorified from a mere sergeant-major, has become a general officer. The assertion that Tweedy fought in the battle of Rorke's Drift against the Zulus in 1882 may also be fantastic: nothing else in the novel confirms it.
Challenged by a constable to name his "Regiment," Bloom "Turns to the gallery" and affirms his connection with Tweedy's outfit: "The royal Dublins, boys, the salt of the earth, known the world over. I think I see some old comrades in arms up there among you. The R. D. F., with our own Metropolitan police, guardians of our homes, the pluckiest lads and the finest body of men, as physique, in the service of our sovereign." Someone accuses Bloom of being a "Turncoat" who supported the Boers against the British cause, and he asserts that he fought in the Second Boer War "and was disabled at Spion Kop and Bloemfontein, was mentioned in dispatches."
Later in the episode, when Stephen is trouble with two soldiers, Bloom tells them that "We fought for you in South Africa, Irish missile troops. Isn't that history? Royal Dublin Fusiliers. Honoured by our monarch." The air of fantastical elaboration still clings in the phrase "missile troops." Fusil is French for a long gun, and the first fusiliers in the late 17th century carried flintlock muskets.