The Decline and Fall of the Roman Empire
In Volume I, especially Chapters XV and XVI, Gibbon challenged Church history. He estimated far smaller numbers of Christian martyrs than had been previously thought. The Church's version of its early history had rarely been questioned before. For Gibbon, however, the Church writings were secondary sources. He shunned them in favour of primary sources from the period he was writing about. This is one reason why Gibbon is referred to as the "first modern historian".