There is disclosed an auxiliary rotation device 28 for a gas turbine engine 10. The auxiliary rotation device 28 comprises: an electric machine 30 configured to be coupled to a rotor of the gas turbine engine 10; and a dedicated electrical storage device 32 coupled to the electric machine 30. During a period of powered operation of the gas turbine engine 10 the electric machine 30 is configured to act as a generator so as to charge the dedicated electrical storage device 32. Following the period of powered operation of the gas turbine engine 10 the electric machine 30 is configured to act as a motor by discharging the dedicated electrical storage device 32 so as to cause the rotor to rotate for a period of time to provide even cooling of the rotor around its circumference. There is also disclosed a method of cooling a rotor of a gas turbine engine 10 using an auxiliary rotation device 28.