First appearance of Weyoun.
This episode featured the second Iconian gateway after its introduction in Contagion (1989). Some of the places shown in the Iconian gateways are Starfleet Command, Paris, and Bajor.
Plot reveals that The Dominion has been in existence for over 2000 years - which would put its emergence around the 4th century A.D. on Earth.
This episode was directed by LeVar Burton, who played Geordi La Forge in Star Trek: The Next Generation (1987). It was his fifth Deep Space Nine episode overall, and the first of five Jem'Hadar-related episodes which he directed.
Worf says he was part of the mission that discovered the Iconian gateways. This is true. In Contagion (1989), the three characters who beamed down to Iconia were Picard, Data and Worf.