[As that seems to be a statement rather than a question about magic, Jeeves simply nods.]

That is a somewhat complicated question to answer, madam. My native land of England has existed as a political state for some 1,000 years. Its precise geographical boundaries and the interplay of political governance and rule has shifted in that time, however. Great Britain, the broader term for my nation as it encompasses all lands ruled by His Majesty, has existed for a little over 200 years.

May I inquire as to how long you have guided your nation?