The Battle of Mygeeto was one of the longest battles of the Clone Wars, lasting for two years and beginning in 21 BBY. In 19 BBY, it became part of the Galactic Republic’s Outer Rim Sieges to secure the planets of the Outer Rim Territories.
When Supreme Chancellor Palpatine issued the Declaration of a New Order, General Mundi was still on Mygeeto, commanding Republic forces. As General Mundi rallied his troops on a bridge spanning a chasm between two city blocks, with enemy droids destroying several UT-ATs, Commander Bacara was contacted through a secure, holographic comlink that was frequency-locked to a channel reserved for the Commander-in-Chief. The hologram was of a hooded and severely disfigured Darth Sidious, Dark Lord of the Sith, ordering him that it was time to execute Order 66.
Bacara complied and moments later, on his order, the clones nearest General Mundi suddenly stopped fighting. Confused, Ki-Adi-Mundi turned around and was blasted by clone fire. The surprised Jedi Master managed to kill three Marines by deflecting their fire before succumbing to his troops’ fire.
In To the Vanishing Point, the battle in which Rivi-Anu perished was supposed to have taken place on a different world from Mygeeto. However, The Complete Star Wars Encyclopedia‘s authors established in Rivi-Anu’s entry that the events of the story took place on Mygeeto.