Original: The Laws in Wales Acts of 1535 -- 42 annexed Wales as part of England , the 1707 Acts of Union brought England and Scotland together under the Parliament of Great Britain , and the 1800 Act of Union included Ireland under the Parliament of the United Kingdom and Ireland .
Simplified: The 1707 Acts of Union brought England and Scotland together under the Parliament of Great Britain , and the 1800 Act of Union included Ireland under the Parliament of the United Kingdom .