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).