It is possible that Gaozu had begun planning his retirement as early as 623. According to the Jiu Tang shu biography of Pei Ji, in 623 the latter requested Gaozu's permission to retire from active court service. Pei Ji noted that he was old and that the work of consolidating Tang imperial control had been accomplished. Gaozu allegedly cried and said, "Not yet. We will mutually support each other in our old age. You will be one of the highest honorific courtiers and I will be taishang; we will spend our days happy and carefree."引自 THE XUANWU MEN INCIDENT OF THE TANG
In 576, Houzhu of the Northern Qi regime tried this tactic and found himself bereft of an empire--directly wagering imperial prestige on military enterprises is a risky gamble. Judged from the 'aesthetics' of factional manipulation, Taizong was a second rate performer. 引自 THE PREVASIVE FACTIONALIZATION OF TAIZONG'S COURT
