《旧五代史·后梁·列传四》
当时王重盈的儿子王珙任陕州节度使，王瑶任绛州刺史，因此争当蒲州主帅，王瑶、王珙连上奏章论理，又写信给太祖说 ：王珂不是我的兄弟，只不过是我家的一个家奴，小字叫忠儿，哪能继位！ 
时重盈子珙为陕州节度使，瑶为绛州刺史，由是争为蒲帅，瑶、珙连上章论列，又与太祖书云： 珂非吾兄弟，盖余家之苍头也，小字忠兒，安得继嗣！ 
At that time, Wang Chongying's son Wang Gong was the Jiedushi of Shaanzhou, and Wang Yao was the governor of Jiangzhou. They both competed to be the commander of Puzhou. Wang Yao and Wang Gong wrote to the emperor, arguing: "Wang Ke is not my brother, he is just a servant in my family, his nickname is Zhong'er, how can he succeed to the throne!"