Secretary of State (United Kingdom)
In the United Kingdom, a Secretary of State (SofS) is a Cabinet Minister in charge of a Government Department (though not all departments are headed by a Secretary of State, e.g. HM Treasury is headed by the Chancellor of the Exchequer).
There are a number of Secretaries of State, each formally titled "Her Majesty's Principal Secretary of State for ...". Legislation generally only refers to "The Secretary of State" without specifying which one; by virtue of the Interpretation Act 1978 this phrase means "one of Her Majesty’s Principal Secretaries of State". These positions can be created without primary legislation, nowadays at the behest of the Prime Minister.
History
Kingdom of England
In the Middle Ages the kings of England were attended by a cleric called their "king's clerk" and later "secretary", who dealt with their correspondence. Until Henry VIII, there was usually only one secretary, but under him a second appeared. In the time of Elizabeth I (1558–1603) these men gained the title "Secretary of State". With Cabinet government after 1688, the Secretaries of State took on higher duties. Their posts came to be known as the Secretary of State for the Northern Department and the Secretary of State for the Southern Department. Both dealt with Home Affairs, but they divided Foreign Affairs, so that one dealt with the Protestant states of northern Europe and the other with the Roman Catholic states of southern Europe.