The song that the Doctor and Seven sing in the mess hall is the same song that Worf sang in The Way of the Warrior (1995).
Mark Tobin, who plays an unnamed Klingon in this episode, previously played a Klingon over thirty years earlier in Day of the Dove (1968). Before that he played Khan's right-hand man Joaquin in Space Seed (1967).
The death of the Klingon gods was first mentioned in Homefront (1996) and as part of the Klingon wedding ceremony in You Are Cordially Invited (1997).
This is the second of two Voyager episodes written by TNG/DS9 writer Ronald D. Moore and the last Star Trek episode written by him.
At 6:23, Neelix mentions a story about a famous Klingon, Sarpek the Fearless, accidentally unearthing the "Knife of Kiromm" while trying to find his lost targ. The Knife of Kiromm, which has the blood of Kahless on the blade, was originally mentioned in Rightful Heir (1993).