The significant conflict known as the Battle of Xagobah unfolded during the Clone Wars. It commenced sixteen months following the Battle of Geonosis, specifically in 21 BBY, and its duration extended until the commencement of the Outer Rim Sieges. This battle transpired simultaneously with the attempted assassination of Techno Union Foreman Wat Tambor by Boba Fett.
Following a retreat from a Republic offensive within the Core and Colonies regions, the Confederacy of Independent Systems initiated the assembly of a large portion of its fleet at fortified locations in the Outer Rim Territories, aiming to lure the Republic forces. Xagobah functioned as one of these fortress worlds, providing refuge for Techno Union Foreman Wat Tambor and housing his Mazariyan citadel.
Driven by the desire to capture Tambor, the Republic dispatched a force under the command of Jedi Master Glynn-Beti to besiege Xagobah. Unbeknownst to the Republic, a high-ranking Senate official had issued bounties for the capture of Separatist leaders, making Wat Tambor a target for the young bounty hunter Boba Fett. The Republic deployed an Acclamator-class assault ship to oversee the battle from orbit, while Glynn-Beti and her Padawan Ulu Ulix spearheaded the ground assault, and skilled starfighter pilot Anakin Skywalker delivered aerial support.
Following the initial attack, numerous clone troopers, walkers, LAAT/is, and starfighters encircled the fortress, subjecting it to bombardment from entrenched positions. Simultaneously, a battle droid army advanced from a nearby devastated city to attempt to break the siege. In an effort to neutralize the Republic's air superiority, Wat Tambor programmed a drone ship to collide with the orbiting assault ship. Anticipating this maneuver, Ulu Ulix commandeered a swoop and accelerated towards the ramship, only to be shot down by enemy fire. Boba Fett intervened, rescuing the falling Ulu, and delivering the young Jedi back to Glynn-Beti.
As Boba Fett approached the citadel walls, Tambor's forces launched a counteroffensive. Thousands of battle droids and droidekas surged from Mazariyan to engage the clone army. At this juncture, Anakin Skywalker led a squadron of Jedi interceptors in an assault on the fortress, successfully breaching a significant hole in its structure. A Hailfire droid launched a barrage of missiles at Anakin's starfighter, but the skilled pilot evaded the projectiles, causing them to strike the ramship and trigger its detonation. The resulting energy surge temporarily disrupted the battle droids' circuits, enabling Boba Fett to infiltrate the Mazariyan citadel through the opening created by Republic fire.
While the external battle raged, Boba Fett confronted Wat Tambor, attempting to assassinate him. However, the Techno Union Foreman managed to escape with the assistance of General Grievous, who had arrived on Xagobah with Confederate reinforcements. Despite his youth at only 12 years old, the young bounty hunter engaged in combat, narrowly escaping with his life. As Boba Fett departed in Slave I, he was attacked by Asajj Ventress. Slave I sustained considerable damage, but Anakin Skywalker repaired it on a nearby asteroid. Following this event, the Siege of Xagobah continued for several months, ultimately leading to the Confederacy's surrender of the world to the Republic.