This episode was Tim Minear's directorial debut. He says he felt it was time to explore Darla's history, which "should really be her story with Angel throughout the 150 years that they were together." When Joss Whedon pointed out that they were already doing a Spike origin story on Buffy the Vampire Slayer (1997), Minear suggested they do both.
Julie Benz says the flashback scenes are "the high points" of playing Darla; her favorite scene is the Boxer Rebellion.
During the flashback to the Boxer Rebellion in 1900, Spike mentions killing a Slayer. This would be Xin Rong, the first Slayer he killed, which he recounts in Fool for Love (2000). This fight is the source of Spike's scar, which is still freshly bleeding in the flashback.
The crossover episode Fool for Love (2000) aired earlier the same night: November 14, 2000. Complementing each other, the Buffy episode features flashbacks to the events at the Boxer rebellion from Spike's point of view.
However, the episode also has a shot that mirrors a shot from the previous Buffy episode, No Place Like Home (2000), where Buffy jumps through a high window with the dying monk in her arms to protect him from Glory. The Angel episode has a shot of Angel jumping through a window, carrying the missionaries' baby while fleeing from Darla.
Joss Whedon stated this episode as his all-time favorite episode, during an "Attack of the Show" interview.