The Christopher-class was a type of starship in service to the United Earth Space Probe Agency, United Earth Starfleet and later the United Federation of Planets Starfleet, in the 22nd century. They had entered service by the late 2150s and were used extensively during numerous engagements in the Earth-Romulan War. Following the war's end in 2160 and the founding of the Federation in 2161, many of these vessels were incorporated into the new Starfleet. (ST novel: Starfleet: Year One) They were presumably named after early Human astronaut Shaun Geoffrey Christopher.