This page contains information regarding Star Trek: Discovery, and thus may contain spoilers.
Donatu V, known in Klingonese as Dona'tu vaghDaq, was the inhabited fifth planet of its system. The system was located in the same quadrant as Sherman's Planet, Deep Space Station K-7, and an unnamed Klingon outpost. Ownership of this planet, as well as the rest of the region, was disputed between the United Federation of Planets and the Klingon Empire from the point of first contact through the late 2260s.
The Battle of Donatu V, one of the few brush wars fought between the two powers during the Federation-Klingon Cold War, was fought here in 2245. The battle was inconclusive. (TOS: "The Trouble with Tribbles") T'Kuvma referred to the battle in rallying the Klingon High Council to his banner in 2256. (DIS: "Battle at the Binary Stars")
In 2374, during the Dominion War, the Jem'Hadar had destroyed three convoys of Klingon cargo vessels on their way to this planet. For the fourth convoy, the IKS Rotarran was ordered to escort cargo vessels, which included the IKS Par'tok, to Donatu V. The mission was a success. (DS9: "Sons and Daughters")