English units are the historical units of measurement used in England up to 1826 (when they were replaced by Imperial units), which evolved as a combination of the Anglo-Saxon and Roman systems of units. Various standards have applied to English units at different times, in different places, and for different applications. The two main sets of English units were the Winchester Units, in effect from 1495–1587, as reaffirmed by King Henry VII, and the Exchequer Standards, in effect from 1588–1825, as first defined by Queen Elizabeth I.