The museum became a construction site as Sir Robert Smirke's grand neo-classical building gradually arose.
The King's Library, on the ground floor of the East Wing, was handed over in 1827, and was described as one of the finest rooms in London.
Although it was not fully open to the general public until 1857, special openings were arranged during The Great Exhibition of 1851.
In spite of dirt and disruption the collections grew, outpacing the new building.

In 1840, the museum became involved in its first overseas excavations, Charles Fellows's expedition to Xanthos, in Asia Minor, whence came remains of the tombs of the rulers of ancient Lycia, among them the Nereid and Payava monuments.
In 1857, Charles Newton was to discover the 4th-century BC Mausoleum of Halikarnassos, one of the Seven Wonders of the Ancient World.
In the 1840s and 1850s the museum supported excavations in Assyria by A.H. Layard and others at sites such as Nimrud and Nineveh.
Of particular interest to curators was the eventual discovery of Ashurbanipal's great library of cuneiform tablets, which helped to make the museum a focus for Assyrian studies.

Sir Thomas Grenville (1755–1846), a trustee of the British Museum from 1830, assembled a library of 20,240 volumes, which he left to the museum in his will.
The books arrived in January 1847 in twenty-one horse-drawn vans.
The only vacant space for this large library was a room originally intended for manuscripts, between the Front Entrance Hall and the Manuscript Saloon.
The books remained here until the British Library moved to St Pancras in 1998.
The museum became a construction site as Sir Robert Smirke's grand neo-classical building gradually arose. The King's Library, on the ground floor of the East Wing, was handed over in 1827, and was described as one of the finest rooms in London. Although it was not fully open to the general public until 1857, special openings were arranged during The Great Exhibition of 1851. In spite of dirt and disruption the collections grew, outpacing the new building.
In 1840, the museum became involved in its first overseas excavations, Charles Fellows's expedition to Xanthos, in Asia Minor, whence came remains of the tombs of the rulers of ancient Lycia, among them the Nereid and Payava monuments. In 1857, Charles Newton was to discover the 4th-century BC Mausoleum of Halikarnassos, one of the Seven Wonders of the Ancient World. In the 1840s and 1850s the museum supported excavations in Assyria by A.H. Layard and others at sites such as Nimrud and Nineveh. Of particular interest to curators was the eventual discovery of Ashurbanipal's great library of cuneiform tablets, which helped to make the museum a focus for Assyrian studies.
Sir Thomas Grenville (1755–1846), a trustee of the British Museum from 1830, assembled a library of 20,240 volumes, which he left to the museum in his will. The books arrived in January 1847 in twenty-one horse-drawn vans. The only vacant space for this large library was a room originally intended for manuscripts, between the Front Entrance Hall and the Manuscript Saloon. The books remained here until the British Library moved to St Pancras in 1998.
British Museum