Battle of Mon Cala/Legends

"The Mon Calamari system must not fall into Separatist hands. Prepare for an assault."

- Jedi Master Mace Windu, to Anakin Skywalker, Padmé Amdiala, and Captain Ackbar

A battle for control of the planet Mon Calamari occurred around 21 BBY during the Clone Wars, when the Quarren-backed Confederacy of Independent Systems attempted to seize the Calamari system from the Mon Calamari people and the Galactic Republic. The Jedi Order intervened in the conflict, bringing reinforcements from the Grand Army of the Republic and the Gungan Grand Army.

Prelude
"Generals, I regret to inform you that the situation here is grave. While my people remain loyal to the Republic, the Separatists are making advances on the system, and may soon threaten our home planet."

- King Yos Kolina, to Generals Plo Koon and Anakin Skywalker

Around 21 BBY during the Clone Wars, tensions between the planet Mon Calamari's native people and Quarren inhabitants began to escalate. Although King Yos Kolina, allied with the Galactic Republic, mediated the disputes, General Grievous soon led a Confederate invasion of the Calamari system. The Republic proved unable to repel Grievous's forces during the Mission to Iceberg Three, and the further assassination of Kolina left Mon Calamari–Quarren tensions unchecked. While the Republic dispatched Jedi General Anakin Skywalker and Senator Padmé Amidala to Mon Calamari to settle the conflict, the Separatists sent their own envoy, Riff Tamson.

The battle
"This isn't going to be easy!"

- Anakin Skywalker, to Prince Lee-Char

Full-scale battle eventually erupted on Mon Calamari, with Tamson leading the Quarren-backed Separatists against the Mon Calamari and the Republic forces under the command of Skywalker, Amidala, Captain Ackbar, and Prince Lee-Char. Despite reinforcements in the form of clone SCUBA troopers led by Jedi General Kit Fisto and Jedi Commander Ahsoka Tano, and the later addition of the Gungan Grand Army, the Republic encountered difficulties with securing the system from Separatist control.