The title refers to the Fenian Brotherhood which was dedicated to the establishment of an independent Irish Republic in the 19th and early 20th century. It was established in the United Sates in 1858.
Another "Maverick" series inside joke that gets lost in time: when Col. Gaylord Summers tells Beauregard Maverick that he has "no time for sergeants," he is referencing the title of the hit Broadway play of 1955-57 and the film version of it (No Time for Sergeants (1958)).
Arthur Shields (as Terence Fogarty) asks Beau Maverick whether he is "Going my way?" This is a sly reference to the film "Going My Way", for which Shields' brother, Barry Fitzgerald, won an Academy Award.
Actress Sharon Hugueny had her first onscreen kiss, with Roger Moore, in this episode.