The Cardinal started life -briefly- as a ship of the Galactic Republic diplomatic corps. It was dispatched directly from the factory on Corellia to pick up diplomats on Utapau with only it's serial number to identify it. Unfortunately, on its inaugural trip it was intercepted by Seperatist ambush. The ship was captured, thinking that it held republic officials. When they realized it was empty, but en-route to pick up diplomats, they tried to use the still-unnamed corvette as a kidnapping trap.
The trap worked, but the Separatists didn't expect for the diplomats to fight back. They retook the ship from the complement of b1 battle droids tasked with secreting the hostages away. With a minimal crew, the republic diplomats then out-flew Seperatist ships and returned to republic space.
The diplomats decided the ship should be named for the grave mistake the Separatists made in trying to kidnap them and was named the Cardinal Underestimation. More than a few of the ship's crew rolled their eyes at the choice and in less than a week merely called it the Cardinal.
The Cardinal continued in the Diplomatic Corps through the remainder of the Clone War. When the Empire replaced the Republic, the Cardinal was given field upgrades. Additional point defenses to make it even more dangerous to fighters. It was then assigned to a fleet in the Expansion region. The Cardinal saw little real action and was soon decommissioned as the Empire began replacing Clone War era Republic ships with Imperial Star Destroyers and Raider corvettes.
Instead of being sold off to some system defense force, it was grounded on Ord Cestus and abandoned. Like a lot of ships that found their way into the Rebellion, a rebel cell rediscovered what the Empire had cast aside. With some effort the ship was made space-worthy again. From there they used the corvette to break imperial blockades, deliver supplies and help people escape Imperial held worlds. The Cardinal joined the larger rebel fleet after Yavin.
From there, with its extra point defense, it bounced around different battle groups, protecting larger capital ships from TIE fighters.
The Cardinal was absent from the Battle of Endor. It was tasked with shuttling supplies to secret caches as a contingency if the rebellion failed to destroy the second Death Star.
Needing ships for the new battle group, the Cardinal was tapped to resume its role as a picket ship.