Fang Xuanling
After Emperor Gaozu's death in 635, Emperor Taizong began building the imperial temples to worship his ancestors (including his father). The chancellor Fang Xuanling suggested that Emperor Gaozu's seventh-generation ancestor, Li Gao (the founder of the Sixteen Kingdoms period state Western Liang) be honored as the main Tang ancestor, but Yu opposed, arguing that Tang's imperial powers did not originate from Li Gao, and therefore Li Gao should not be honored as the main ancestor. Emperor Taizong agreed.