The Parliament of the United Kingdom of Great Britain and Northern Ireland is the highest political-legislative and legislative body in the United Kingdom and British overseas territories. It alone has parliamentary sovereignty over all other political bodies. The parliament has an upper house, the House of Lords, and a lower house, the House of Commons. At its head is the monarch, King Charles III. The monarch is the third part of Parliament. The British people choose the people in the lower house (members of parliament) in elections.
The development of parliament started with the councils of bishops and earls that advised the kings and queens of the Middle Ages. In 1707, during the early modern period, the Parliament of England and the Parliament of Scotland joined to become the Parliament of Great Britain. The first Parliament of the United Kingdom came into existence in 1801, after the Irish Parliament joined with the Parliament of Great Britain. Between 1801 and 1927, the British legislature's name was the Parliament of the United Kingdom of Great Britain and Ireland.