Phorose existed as a planet situated within the region known as the Colonies.
Long before the Clone Wars transpired, Phorose was the site of ancient temples and cities that had been constructed. In those times, the Galactic Republic engaged in battles against the Confederacy of Independent Systems, striving to hinder the Confederacy's planned invasion of the world. The Republic's forces, under the command of Jedi Master Plo Koon alongside Padawans Barriss Offee and Ahsoka Tano, successfully repelled the Separatist Droid Army; however, this defense resulted in the devastation of a large portion of the capital city.
During the course of the conflict, Jedi Offee made an attempt to save a group of indigenous Ru but ultimately failed to shield them from death within the battle. This incident, where she believed the Republic and the Jedi Order bore responsibility for their demise, significantly fueled Offee's growing disillusionment with the Republic's involvement in the war and the Jedi's role in it.