One of the greatest of all Anglo-Saxon treasures, the oldest complete Latin Bible in existence, is returning to the UK for the first time in 1,302 years.

The Codex Amiatinus is a beautiful and giant Bible produced in Northumbria by pioneering monks in 716 which, on its completion, was taken to Italy as a gift for Pope Gregory II.

On Thursday, the British Library announced it had secured its loan from the Laurentian library in Florence for a landmark exhibition in 2018 on the history, art, literature and culture of Anglo-Saxon England.

“It is the earliest surviving complete Bible in Latin,” said Claire Breay, the library’s head of medieval manuscripts. “It has never been back to Britain in 1,302 years but it is coming back for this exhibition. It is very exciting.”

The Bible is considered one of the most stupendous surviving treasures from Anglo-Saxon England but is not widely known about outside academic circles.

“I’ve been to see it once and it is unbelievable,” said Breay. “Even though I’d read about it and seen photographs, when you actually see the real thing … it is a wonderful, unbelievably impressive manuscript.”

Part of its power is its sheer size. It is nearly half a metre high and weighs more than 34kg (75lb), and more than a thousand animal skins were needed to make its parchment.

It was one of three commissioned by Ceolfrith, the abbot of Wearmouth-Jarrow monastery, and was a mammoth undertaking, said Breay. Of the others, one is lost and another exists in small fragments at the British Library.

Ceolfrith himself was part of the team of monks who took the Bible to Italy, but he never got to see it arrive because he died on the journey, in Burgundy.

There is evidence of it arriving and, at some point, it made its way to the monastery in San Salvatore, Tuscany, before arriving, in the late 18th century, at the Laurentian library where it has remained one of the greatest treasures.

The Codex Amiatinus will go on display alongside the Lindisfarne Gospels and some of the most spectacular illuminated manuscripts that exist anywhere including the Benedictional of St Æthelwold, which includes the earliest surviving image of the three wise men wearing crowns.

Breay said the autumn exhibition would shine light on the sophistication of Anglo-Saxon culture, a period often dismissed as the Dark Ages.

Another coup will be the loan, again from Italy, of an important manuscript of Old English poetry known as the Vercelli Book. Dating from the 10th century, it returns to the UK for the first time and is being lent by the Biblioteca Capitolare in Vercelli.

It is one of four manuscripts known as the Old English Poetic Codices, the others being the British Library’s manuscript of Beowulf, the Junius manuscript at the Bodleian library in Oxford and the Exeter Book from Exeter Cathedral library. All four will be on display together for the first time.

Also on show will be the oldest surviving will left by a woman (Wynflaed), who lists her estates, slaves, horses, tapestries, dresses, headbands, seat cushions, bed curtains, wooden chests, metal cups, jewellery and coins; and the earliest surviving original letter, sent by the bishop of London to the archbishop of Canterbury in 704 or 705, asking permission to attend a meeting to resolve disputes between neighbouring Saxon kingdoms.

The Anglo-Saxon show was announced as part of a 2018 exhibition programme which also includes one on Captain James Cook, marking 250 years since he set sail on Endeavour on the first of his three world-changing voyages.

The 70th anniversary of the arrival of the cruise ship Empire Windrush in Essex, carrying hundreds of Caribbean migrants to Britain, will be marked in an exhibition opening in June.

The library also announced it had acquired the archive of the Booker prize winning novelist Penelope Fitzgerald, who died in 2000. It includes notebooks, drafts and letters shining light on a literary life that gives hope to many aspiring writers as she was 58 when she was first published.