Temporal Offensive

In anticipation of the Flux, the Sontarans waged a Temporal Offensive, known as the Sontaran Temporal Offensive, on Earth, sending timeships back through time and overwriting the planet's history. This offensive was ultimately thwarted by the Thirteenth Doctor and her companions, averting the changes the Sontarans had made. (TV: War of the Sontarans)

Behind the scenes
Before War of the Sontarans, the video game NOTVALID: Legacy opened with the Eleventh Doctor finding the Sontarans waging an offensive across the history of Earth and the universe, beginning a temporal crisis which draws in the Doctors, their companions and numerous enemies.