Sweating sickness first came to the attention of physicians at the beginning of the reign of Henry VII, in 1485. It was frequently fatal; half the population perished in some areas. There is no definitive statement that the sickness was present in troops landing at Milford Haven. Henry arrived in London on 28 August soon after the Battle of Bosworth Field, and the disease broke out on 19 September 1485; it had killed several thousand people by its conclusion in late October that year. Among those killed were two lord mayors, six aldermen, and three sheriffs.