Complex sentence: In 1861 construction of the Royal Museum, originally the Industrial Museum, began with Prince Albert laying the foundation stone; in 1866 the eastern end, including the Grand Gallery, was opened by Prince Afred.
Split into simpler sentences: In 1861 construction of the Royal Museum, originally the Industrial Museum, began with Prince Albert laying the foundation stone. In 1866, the eastern end, including the Grand Gallery, was opened by Prince Afred.