USS Surya Class Frigate

The first frigate-type starship built by the Federation was the Surya class ship. Oddly enough, this ship was designed primarily by the Vulcans during their war with the Klingons in the 2170s. As the Klingons and Vulcans decimated their large-scale starships, both sides moved towards smaller, fast and maneuverable starships that could cover more space in a shorter amount of time. The large ships like the D'Kyr and Qoi-Veqlargh Qaw class Command Ship were quickly succumbing to the faster and smaller starships like the D4 and Surak class.
As the Klingon-Vulcan war entered a lull due to starship attrition, a period of re-armament began and the Vulcans knew that their failure to deter the Klingons from entering Federation space by diplomacy and then by force meant the Federation itself would be threatened. Therefore, a new class of starship was needed that could give the Federation the time it needed to prepare for the inevitable invasion of Federation space by the Klingon Empire and the Vulcans the leeway to further their diplomatic efforts with the Klingon Empire.
The Surya class frigate was the first ship designed to meet this challenge.
It was not a pure warship, in fact, it was more of an armed police vessel than a combat ship, but, it was a capable combat vessel and could go head-to-head with any Klingon D4 or smaller vessel (which comprised the bulk of the Klingon Starfleet).