Unlike earlier religious revivals based on powerful preaching, the revival of 1904–05 relied primarily on music and on alleged supernatural phenomena as exemplified by the visions of Evan Roberts. The intellectual emphasis of the earlier revivals had left a dearth of religious imagery that the visions supplied. The visions also challenged the denial of the spiritual and miraculous element of Scripture by opponents of the revival, who held liberal and critical theological positions. The structure and content of the visions not only repeated those of Scripture and earlier Christian mystical tradition but also illuminated the personal and social tensions that the revival addressed by juxtaposing Biblical images with scenes familiar to contemporary Welsh believers.