Why is headless horseman is unfriendly?

Historical fiction is concerned with depicting historical figures and events in a new light. in this excerpt from arthur conan doyle's "the contest," which two sentences most clearly describe historical elements? policles sprang readily to his feet at the challenge, and the great company making way for him to pass, he found himself a minute later standing in his unkempt garb, with his frayed and weather-beaten harp in his hand, before the expectant crowd. he stood for a moment tightening a string here and slackening another there until his chords rang true. then, amid a murmur of laughter and jeers from the roman benches immediately before him, he began to sing. he had prepared no composition, but he had trained himself to improvise, singing out of his heart for the joy of the music. he told of the land of elis, beloved of jupiter, in which they were gathered that day, of the great bare mountain slopes, of the swift shadows of the clouds, of the winding blue river, of the keen air of the uplands, of the chill of the evenings, and the beauties of earth and sky. it was all simple and childlike, but it went to the hearts of the olympians, for it spoke of the land which they knew and loved. yet when he at last dropped his hand, few of them dared to applaud, and their feeble voices were drowned by a storm of hisses and groans from his opponents. he shrank back in horror from so unusual a reception, and in an instant his blue-clad rival was in his place. if he had sung badly before, his performance now was inconceivable. his screams, his grunts, his discords, and harsh jarring cacophonies were an outrage to the very name of music.