Seen in its wider social context, Greek Revival architecture sounded a new note of sobriety and restraint in public buildings in Britain around 1800 as an assertion of nationalism attendant on the Act of Union, the Napoleonic Wars, and the clamour for political reform. It was to be William Wilkins's winning design for the public competition for Downing College, Cambridge that announced the Greek style was to be the dominant idiom in architecture. Wilkins and Robert Smirke went on to build some of the most important buildings of the era, including the Theatre Royal, Covent Garden (1808–09), the General Post Office (1824–29) and the British Museum (1823–48), Wilkins University College London (1826–30) and the National Gallery (1832–38). In Scotland, Thomas Hamilton (1784–1858), in collaboration with the artists Andrew Wilson (1780–1848) and Hugh William Williams (1773–1829) created monuments and buildings of international significance; the Burns Monument at Alloway (1818) and the (Royal) High School in Edinburgh (1823–29).

Answer this question, if possible (if impossible, reply "unanswerable"): In what year was the British Museum built?
1823–48