The Time Lords, under the leadership of Lady President Romana, decided that it was in the better interests of the universe if Gallifrey shared its time travel technology - and the responsibility for the Web of Time with other time-active races. The Time Lords set a conference on the planet Archetryx to work out the agreements.
The Daleks collided the planet Etra Prime into Archetryx to disrupt the agreements and attempt a takeover of Gallifrey. Their efforts were ultimately unsuccessful, and it gave the factions the incentive to sign the agreements as the Temporal Powers. The Powers were left to rebuild following the devastating invasions of their respective homeworlds by the Daleks which had occurred during the incident, with Romana promising that Gallifrey would provide aid. (AUDIO: The Apocalypse Element)
Part of the agreements allowed for off-world students to attend the Time Lord Academy on Gallifrey. This move was resisted by conservative elements on Gallifrey led by Inquisitor Darkel. (AUDIO: Insurgency, Imperatix)
During the Civil War on Gallifrey, Romana desperately tried to keep the students of the other powers safe, however after her defeat of the Imperiatrix Pandora, a number of the other Temporal Powers attempted to rescue their students and at the same time occupy Gallifrey. (AUDIO: Appropriation)
On the fringes of the Last Great Time War, the Temporal Powers had a local skirmish between several of their members. (PROSE: Ghost of Christmas Past) The extermination or near-extermination of such Temporal Powers as the Monans, the Sunari, the Nekkistani and the Phaidonians by the Daleks led to Gallifrey formalising the Time War. (AUDIO: Desperate Measures)