Galaxy class (23rd century)
The Galaxy-class starship was a class of Starfleet vessel mentioned in the Treaty of Armens from that year. It was stated in the treaty, that a UFP official from the Cultural Contact Office (Sol Sector) shall be on board a Galaxy-class Starfleet vessel at all times except during legal holidays.

There were at least two classes named Galaxy-class; the other was in operation a century later. ( display graphic)

 

Federation starship classes