On 11 December 2007, Gillard was acting prime minister while Rudd attended the United Nations Climate Change Conference in Bali, becoming the first woman ever to hold that position. She assumed these duties for a total of 69 days throughout Rudd's tenure, during his various overseas travel engagements. Gillard quickly became known as a highly regarded debater, with her performances during parliamentary question time prompting Peter van Onselen to call her "the best parliamentary performer on the Labor side".