Gungan–Naboo War

The Gungan-Naboo War was fought among the Naboo and Gungans.

Origins
Prior to the war, conflict between the Gungans and Naboo were rare, if not nonexistent.

It is unknown how the war began, but the Jafan Dynasty that reigned expired c.150 BBY when the last heir died. Without a ruler, the Naboo elected a Queen to lead them in the war.

Aftermath
The conflict ended in 121 BBY.

Upon the queen's death, she instituted an elected, rather than hereditary, monarchy. The conflict apparently ended in 121 BBY.

Behind the scenes

 * There is contradictory information on whether the Gungan-Naboo War ever occurred. One source states that the war occurred between 150 BBY and 121 BBY. The The New Essential Guide to Alien Species states that there was never a war between the Gungans and Naboo.