Passage: On his retirement, Mahathir was named a Grand Commander of the Order of the Defender of the Realm, allowing him to adopt the title of "Tun". He pledged to leave politics "completely", rejecting an emeritus role in Abdullah's cabinet. Abdullah immediately made his mark as a quieter and less adversarial premier. With much stronger religious credentials than Mahathir, he was able to beat back PAS's surge in the 1999 election, and lead the Barisan Nasional in the 2004 election to its biggest win ever, taking 199 of 219 parliamentary seats.Mahathir was the CEO and Chairman, and hence a senior adviser, to many flagship Malaysian companies such as Proton, Perdana Leadership Foundation and Malaysia's government-owned oil and gas company Petronas. Mahathir and Abdullah had a major fallout over Proton in 2005. Proton's chief executive, a Mahathir ally, had been sacked by the company's board. With Abdullah's blessing, Proton then sold one of its prise assets, the motorcycle company MV Agusta, which was bought on Mahathir's advice. Mahathir also criticised the awarding of import permits for foreign cars, which he claimed were causing Proton's domestic sales to suffer, and attacked Abdullah for cancelling the construction of a second causeway between Malaysia and Singapore. Mahathir complained that his views were not getting sufficient airing by the Malaysian press, the freedom of which he had curtailed while prime minister: he had been named one of the "Ten Worst Enemies of the Press" by the Committee to Protect Journalists for his restrictions on newspapers and occasional imprisonment of journalists. He turned to the blogosphere in response, writing a column for Malaysiakini, an online media news website, and starting his own blog. He unsuccessfully sought election from his local party division to be a delegate to UMNO's general assembly in 2006, where he planned to initiate a revolt against Abdullah's leadership of the party. After the 2008 election, in which UMNO lost its two-thirds majority in Parliament, Mahathir...

Question: What was Mahathir's new title after he retired?
Tun