Many Star Wars fans know that the Mandalorians have been a pretty big part of the franchise over the years.
Mandalorians have been established in the Expanded Universe and currently-accepted canon as some of the fiercest warriors of that galaxy far, far away, which led fans to wonder where they were during the original trilogy.
Mandalorians also had a prominent role in The Clone Wars as a warrior race being ruled by a determinedly pacifistic leader by the name of Satine.
The closest we got to on-screen Mandalorians in the trilogy was Boba Fett (who is technically a clone in current canon) in his Mandalorian armor.