The Cardassian Union designed the Thalkar Heavy Frigate for multiple mission types, primarily planetary defense and system patrols. The Thalkar frigate also was to be capable of performing escort duties for larger warships. To this end, the Thalkar's shields were heavily reinforced to make it capable of withstanding enemy weapons fire and its engines were optimized to make it more maneuverable than the ships it was to be escorting.
By the 2370's, the Thalkar frigates found themselves defending the second tier systems of the Cardassian Union, running routine system patrols and keeping the peace. During the Dominion War this continued for the most part, though towards the end when the war started to go badly these ships were pulled from their secondary positions and flung in the fray to help stem the tide of Allied advances into Dominion territory. Many Thalkars found themselves smashed aside by superior Allied firepower.
After the war, many Thalkar Heavy Frigates lay damage but not destroyed on the many battlefields littering Cardassian space. Some of these were total losses, nothing more than floating detritus, but others were either partially or wholly salvageable. Minor races, raiders, pirates, and other opportunists managed to salvage many such hulls. Because of this, the Thalkar frigate became an all too common sight in raider hands following the Dominion War.