This episode establishes that Surak died of radiation poisoning following the explosion of one or more atomic weapons on Mount Seleya during the the last battle against "those who marched beneath the Raptor's wings" (i.e. those Vulcans that opposed Surak's teaching, eventually becoming the Romulan Star Empire). The allusion of the Raptor's Wing refers to the bird-of-prey symbol that represents the Romulan Star Empire.
The Syrrannites claim to be searching for the "lost" Kir'shara, yet, soon after coming into possession of Surak's Katra, Archer knows where to find the Kir'shara. As Syrran, who previously possessed Surak's Katra, also should have known its location, we must assume that Syrran had a reason for not revealing the location, for example, even to his most trusted follower, T'Pau, who, upon seeing the Kir'shara for the first time, confessed that she doubted if the legendary ancient record still existed. One possible explanation is that Surak's Katra, having survived for 1800 years, patiently waited, intentionally withholding the information, until such time that the Vulcan people were ready for the Kir'shara to take its rightful place. In the episode, Surak's Katra specifically notes the alien ancestry of Archer as an advantage in finding the Kir'shara and bringing it back to the Vulcan people, as if to admit that the appearance of Archer at a crucial moment was too fortuitous to pass up. If true, this shows that a Vulcan Katra can withhold information from its host.
This episode was directed by Roxann Dawson, who played B'Elanna Torres in Star Trek: Voyager (1995). This is the tenth and last episode of "Star Trek" that she directed.
Barry Atwater, who portrayed Surak in The Savage Curtain (1969), could not reprise the role - died in 1978.
The final show in which John Billingsley (Dr. Phlox) does not appear, and also the only one of the fourth season.