[19] At this time, the largest parts of collection were the library, which took up the majority of the rooms on the ground floor of Montagu House, and the natural history objects, which took up an entire wing on the second state storey of the building.

During the few years after its foundation the British Museum received several further gifts, including the Thomason Collection of Civil War Tracts and David Garrick's library of 1,000 printed plays.

[22] From 1778, a display of objects from the South Seas brought back from the round-the-world voyages of Captain James Cook and the travels of other explorers fascinated visitors with a glimpse of previously unknown lands.

The bequest of a collection of books, engraved gems, coins, prints and drawings by Clayton Mordaunt Cracherode in 1800 did much to raise the museum's reputation; but Montagu House became increasingly crowded and decrepit and it was apparent that it would be unable to cope with further expansion.

After the defeat of the French campaign in the Battle of the Nile, in 1801, the British Museum acquired more Egyptian sculptures and in 1802 King George III presented the Rosetta Stone – key to the deciphering of hieroglyphs.

[24] Gifts and purchases from Henry Salt, British consul general in Egypt, beginning with the Colossal bust of Ramesses II in 1818, laid the foundations of the collection of Egyptian Monumental Sculpture.

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 1897 the death of the great collector and curator, A. W. Franks, was followed by an immense bequest of 3,300 finger rings, 153 drinking vessels, 512 pieces of continental porcelain, 1,500 netsuke, 850 inro, over 30,000 bookplates and miscellaneous items of jewellery and plate, among them the Oxus Treasure.

This consisted of almost 300 pieces of objets d'art et de vertu which included exquisite examples of jewellery, plate, enamel, carvings, glass and maiolica, among them the Holy Thorn Reliquary, probably created in the 1390s in Paris for John, Duke of Berry.

Around this time, the American collector and philanthropist J. Pierpont Morgan donated a substantial number of objects to the museum,[37] including William Greenwell's collection of prehistoric artefacts from across Europe which he had purchased for £10,000 in 1908.

As a result, the museum was able to quickly commence relocating selected items on 24 August 1939, (a mere day after the Home Secretary advised them to do so), to secure basements, country houses, Aldwych Underground station and the National Library of Wales.

It also created the opportunity to redevelop the vacant space in Robert Smirke's 19th-century central quadrangle into the Queen Elizabeth II Great Court – the largest covered square in Europe – which opened in 2000.

[55] The Greek Revival façade facing Great Russell Street is a characteristic building of Sir Robert Smirke, with 44 columns in the Ionic order 45 ft (14 m) high, closely based on those of the temple of Athena Polias at Priene in Asia Minor.

Together, they illustrate every aspect of the cultures of the Nile Valley (including Nubia), from the Predynastic Neolithic period (c. 10,000 BC) through Coptic (Christian) times (12th century AD), and up to the present day, a time-span over 11,000 years.

Thereafter, the UK appointed Henry Salt as consul in Egypt who amassed a huge collection of antiquities, some of which were assembled and transported with great ingenuity by the famous Italian explorer Giovanni Belzoni.

The British Museum conducted its own excavations in Egypt where it received divisions of finds, including Asyut (1907), Mostagedda and Matmar (1920s), Ashmunein (1980s) and sites in Sudan such as Soba, Kawa and the Northern Dongola Reach (1990s).

[74] These were donated by Professor Fred Wendorf of Southern Methodist University in Texas, and comprise the entire collection of artefacts and environmental remains from his excavations at Prehistoric sites in the Sahara Desert between 1963 and 1997.

The Cycladic, Minoan and Mycenaean cultures are represented, and the Greek collection includes important sculpture from the Parthenon in Athens, as well as elements of two of the Seven Wonders of the Ancient World, the Mausoleum at Halicarnassus and the Temple of Artemis at Ephesos.

[75] Beginning from the early Bronze Age, the department also houses one of the widest-ranging collections of Italic and Etruscan antiquities outside Italy, as well as extensive groups of material from Cyprus and non-Greek colonies in Lycia and Caria on Asia Minor.

These cover Mesopotamia, Persia, the Arabian Peninsula, Anatolia, the Caucasus, parts of Central Asia, Syria, the Holy Land and Phoenician settlements in the western Mediterranean from the prehistoric period and include objects from the 7th century.

Furthermore, the museum has a representative collection of Dilmun and Parthian material excavated from various burial mounds at the ancient sites of A'ali and Shakhura (that included a Roman ribbed glass bowl) in Bahrain.

Archaeological digs are still taking place where permitted in the Middle East, and, depending on the country, the museum continues to receive a share of the finds from sites such as Tell es Sa'idiyeh [de] in Jordan.

Key benefactors to the department have been Clayton Mordaunt Cracherode, Richard Payne Knight, John Malcolm, Campbell Dodgson, César Mange de Hauke and Tomás Harris.

More than 30,000 British drawings and watercolours include important examples of work by Hogarth, Sandby, Turner, Girtin, Constable, Cotman, Cox, Gillray, Rowlandson, Towne and Cruikshank, as well as all the great Victorians.

Many Bronze Age objects from across Europe were added during the nineteenth century, often from large collections built up by excavators and scholars such as Greenwell in Britain, Tobin and Cooke in Ireland, Lukis and de la Grancière in Brittany, Worsaae in Denmark, Siret at El Argar in Spain, and Klemm and Edelmann in Germany.

In addition, the British Museum's collections covering the period AD 300 to 1100 are among the largest and most comprehensive in the world, extending from Spain to the Black Sea and from North Africa to Scandinavia; a representative selection of these has recently been redisplayed in a newly refurbished gallery.

Important collections include Latvian, Norwegian, Gotlandic and Merovingian material from Johann Karl Bähr, Alfred Heneage Cocks, Sir James Curle and Philippe Delamain respectively.

In the second half of the twentieth century, the museum greatly benefited from the bequest of the philanthropist PT Brooke Sewell, which allowed the department to purchase many objects and fill in gaps in the collection.

The Elgin Marbles, the Benin Bronzes, Ethiopian Tabots and the Rosetta Stone are among the most disputed objects in its collections, and organisations have been formed demanding the return of these artefacts to their native countries.

[159] In January 2025, the British Museum was criticized by Tibetan human rights groups for referring to Tibet as "Xizang," the current preferred term of the government of the People's Republic of China.