Although there was no reliable way of dating periods, there was no shortage of people willing to try. The most well known early attempt30 was made in 1650, when Archbishop James Ussher of the Church of Ireland made a careful study of the Bible and other historical sources and concluded, in a hefty tome called Annals of the Old Testament, that the Earth had been created at midday on 23 October 4004 BC, an assertion that has amused historians and textbook writers ever since.