《旧唐书·列传·卷九十五》
大历三年，加授李忠臣检校工部尚书，实封食邑连先前一共三百户。
大历三年，加检校工部尚书，实封通前三百户。
In the third year of the Dali era, Li Zhongchen was promoted to Inspector of the Ministry of Works, with his fiefdom increased to a total of 300 households.