It's John Knox!
He is known for his influence on Protestant theology and Presbyterianism.
Knox became a leader in the Scottish Reformation in 1546 before and after being imprisoned and exiled in Europe.
His work History of the Reformation in Scotland is an important work in church history.
On his return to Scotland, Knox led the Protestant Reformation in Scotland, in partnership with the Scottish Protestant nobility.
The movement may be seen as a revolution since it led to the ousting of Mary of Guise, who governed the country in the name of her young daughter Mary, Queen of Scots.