For decades they have been part of the collection of the British Museum, appreciated for their individual significance but in many cases shorn of much of their context owing to the circumstances of their discovery and retrieval during the buccaneering period of early archaeology.

Now dozens of important artefacts that were removed from Iraq in the late 19th and early 20th centuries are being brought back into focus in an exhibition drawing on groundbreaking discoveries made by Iraqi archaeologists amid the turbulence of the country’s recent history.

Among the objects on display is a small dolerite statue dating to around 2130BC, purchased by the museum in the 1930s. It depicts a king called Gudea, who ruled the ancient city of Girsu, one of the world’s first urban civilisations, on the site of modern-day Tello in southern Iraq.

The dolerite statue of King Gudea, from 2130BC. Photograph: British Museum

The statue shows him in a position of prayer, as do many others of him, according to Sebastien Rey, a curator of ancient Mesopotamia at the museum. But while experts knew from written sources that Gudea constructed a temple in his city, no trace of it had been found.

That changed thanks to a discovery made through the Iraq emergency heritage scheme, set up by the British Museum in 2015 to train local archaeologists in heritage protection at a time when many of the country’s historical sites were under threat from destruction by Islamists.

By revisiting the site after decades, Rey and a team of local trainee archaeologists discovered not only the site of the king’s 4,000-year-old temple, but also a bakery attached to the temple where huge quantities of bread would have been produced as offerings to the gods.

It is believed to be the first example of this kind of set-up in history, ranking it as an “absolutely 10/10 and beyond” discovery, Rey said.

The purpose of other museum-owned items that have puzzled experts for decades has also become clear as a result of the heritage scheme digs. For example, a collection of inscribed cones: similar items were found inside the temple’s walls as talismanic deposits.

Iraqi law forbids archaeological discoveries from being removed from the country, so the new finds will be represented in photographs, reconstructions and video alongside the museum’s own collection.

The exhibition, titled Ancient Iraq: New Discoveries, will visit the Great North Museum in Newcastle and the University of Nottingham Museum between March and December.