《资治通鉴·唐纪·唐纪二十一》
大食国请求给朝廷进献狮子，姚上疏认为： 狮子专门吃肉，远道运来，肉既难得，极费人力财力。
大食请献师子。姚璹上疏，以为： 师子专食肉，远道传致，肉既难得，极为劳费。
The Arabs requested to send lions to the court. Yao Shu said in his memorial: Lions eat meat, and it takes a lot of manpower and money to transport them from afar, and meat is also hard to find.