Complex sentence: The head came from a painting by Alfred Edward Chalon, drawn for the first public appearance of Victoria as Queen on the occasion of her speech at the House of Lords where she prorogated the Parliament of the United Kingdom in July 1837.
Split into simpler sentences: The head came from a painting by Alfred Edward Chalon, drew for the first public appearance of Victoria as Queen, at the occasion of the speech at the House of Lords. There, as tradition, She prorogated the Parliament of the United Kingdom in July 1837.