I was wondering how a warrior race like the Klingons managed to acquired such an advanced technology, for the Star Trek universe, as cloaking?
The Klingons received the technology in exchange for some battle cruisers from the Romulans around 2268, when the two civilizations shared a political alliance (both startrek.com and the ST:TNG Technical Manual state this).
In TOS:"The Enterprise Incident" - caught in the Neutral Zone, the Enterprise was surrounded by a mixed pack of Romulan warbirds and [what appeared to be] Klingon D7 cruisers (one being the commanding vessel). Spock noted that Star Fleet suspected the Romulans to be using Klingon designed ships, but did not know why because the D7 had no clear advantage over the Romulan warbird ... unless it also was adaptable to the cloaking device [first encountered in TOS:"Balance Of Terror"].
In the animated series episode The Time Trap, the Klingon vessel Klothos (captained by the famous Captain Kor) uses the cloak in the Battle of Caleb IV; as this was 2269, it's likely the earliest mention of Klingons making use of the technology.
Memory Alpha has more information about cloaking technology in the Star Trek universe.
in the past there was an exchange of technology ,200 d-7 klingon decommisioned battle cruisers in exchanged for cloaking techology the romulans had only impulse powered warbirds since the plasma torpedoes took up so much power the KRd-7 klingon bodies with plasma torpedoes installed the warp technology could handle the plasma torpedoes and cloaking devices the klingons reversed engineered the cloaking device so as to cloak ships problem is klingons thought bigger was better so the power requirement became to little up to the bigger ships so the klingons developed the br'el scout ship bird of prey the next in line was the greater bird of prey and finally the great warbird br'en same ship only 3 different sizes the romulans tried to use the ka'tinga but grew out of favor because it was obselete after a while and kept the remember they had time to develop the romulan warbird dedriex class the green 1 that we are familiar with