As an English name it can also derive from the month of August, which was named for the Roman emperor Augustus.
The most notable bearer of the name was Cyrus the Great, the founder of the Achaemenid Persian Empire in the 6th century BC. He is famous in the Old Testament for freeing the captive Jews and allowing them to return to Israel after his conquest of Babylon. As an English name, it first came into use among the Puritans after the Protestant Reformation.
Due to the renown of the saints by this name, Gregory (in various spellings) has remained common in the Christian world through the Middle Ages and to the present day. It has been used in England since the 12th century. A famous bearer from the modern era was American actor Gregory Peck (1916-2003).
As an English Christian name, Isaac was occasionally used during the Middle Ages, though it was more common among Jews. It became more widespread after the Protestant Reformation. Famous bearers include the physicist and mathematician Isaac Newton (1643-1727) and the science-fiction writer Isaac Asimov (1920-1992).
The name was very popular until the 15th century in England, usually in the vernacular form Maud. Both forms were revived by the 19th century. This name appears in the popular Australian folk song Waltzing Matilda, written in 1895.