Tivoli

Tivoli was the most conquered planet in the galaxy. It was inhabited by a species of rodent-like humanoids. They were one of the oldest civilisations in the galaxy and simply let invaders do as they wished. Their anthem was "Glory To  " and their cities were designed to be comfortable for the invading armies. It was green in colour when seen from space. (TV: The God Complex) Its capital city had a sign saying "If you occupied us, you'd be home by now." (TV: Before the Flood)

History
By 1969, the Dominators had conquered the Tivolians, (PROSE: Mutually Assured Domination) but they were later conquered by the Fisher King and his people in 1970, where they ruled for ten years, before being liberated by the benevolent Arcateenians in 1980. The Tivolians did not take kindly to have those oppressing them removed from power. The Arcateenians became so irritated by the Tivolians that they chose to enslave them as well. An undertaker, Albar Prentis, was sent by them to bury the Fisher King on a "barren, savage outpost" in accordance with Arcateenian custom. However, the Fisher King had survived his supposed death but was eventually defeated and killed by the Twelfth Doctor. (TV: Before the Flood)

At some point, Tivoli was conquered by the Hath, until they were overthrown by Ogron invaders on 14 January 2064. The Ogrons were welcomed as invaders. They held the planet until 13 February 2174, when the Uvodni took Tivoli and liberated it from the Ogrons. As with the Ogrons, the Uvodni invaders were welcomes as heroes. Their rulership lasted until 18 March 2293, when the Voord conquered the planet. Though initially welcomed as heroes like the invaders who preceded them, the Voord on Tivoli were wiped out by the Stenza on 4 April 2304. Again, the new conquerers were initially viewed by the Tivolians as heroes. Raxacoricofallapatorians annexed Tivoli on 19 May 2311. In taking the planet from the Stenza, they were welcomed as heroes. The Raxacoricofallapatorians were arrested by the Judoon on 14 June 2426. By placing Tivoli under their jurisdiction, they were regarded as heroes. The Kraal took the world from the Judoon on 9 July 2559. The Terileptils invaded on 12 August 2630 and were viewed as heroes. The Vinvocci wrested Tivoli from the Tereleptils and exiled them on 17 September 2721. The Shakri infiltrated the planet on 17 October 2850. By outmanoeuvering the Vinvocci, they were welcomed as heroes. Later, on 17 November 2900, the Drahvin eradicated the Shakri and took Tivoli for their own. They were welcomed as heroes. The Hath returned on 8 December 3001 and drove out the Drahvin. They were welcomed back to Tivoli as heroes. (PROSE: Time Traveller's Diary)

Gibbis was a native of Tivoli, whose job involved planting trees so that invading forces would be shaded during their marches. (TV: The God Complex)

Behind the scenes

 * In a deleted scene for Before the Flood, Albar Prentis explains that the Arcateenians liberated Tivoli from the Fisher King and his forces by raising the planet's sea level and drowning them, something that worked because the Fisher King came from a barren world. The Tivolians were taken off the planet in slave ships for their own protection while this occurred.