The same story is noted in the "Tale of Heiji", and because Tale of Heike and Tale of Heiji were written at about the same time, there is a possibility of it being literary fiction.
同じ話は『平治物語』にも信頼の逸話として見え、『平治物語』と『平家物語』の成立は同時期と考えられることから、双方ともに文学的虚構である可能性も否定できない。