Forty-five years after the Netherlands promised its return, a gold-inlaid dagger surrendered by a “rebel prince” after his failed 1830 uprising against Dutch rule in Indonesia has been handed back to Jakarta.

The kris, a dagger with a waved blade, was among a number of Prince Diponegoro’s belongings that the Netherlands’ vowed in 1975 to return, only for the cultural treasure to go missing.

The Dutch culture minister, Ingrid van Engelshoven, handed over the blade to the Indonesian embassy in The Hague this week after a two-year search by the Museum of Ethnology in Leiden of its collection.

​​Fery Iswandy, a cultural attache at the Indonesian embassy, said in a statement: “The kris is very important for Indonesia. Diponegoro is our national hero. This attribute of the prince expressed his status.”

Diponegoro is celebrated in Indonesia for a five-year struggle against Dutch rule, known as the Java war. It ended on 28 March 1830 with Diponegoro’s reported surrender of his dagger at the feet of Hendrik Merkus de Kock, the lieutenant governor general of the Dutch East Indies.

Facebook Twitter Pinterest A drawing of the Javanese prince Diponegoro. Photograph: Museum of the Tropics/De Agostini via Getty Images

Diponegoro, a prince on the island of Java, which is now part of Indonesia, was exiled to Celebes, an island east of Borneo, and then to Makassar, the capital of the Indonesian province of South Sulawesi, where he died aged 69.

His dagger was given in 1831 to the royal cabinet of rarities of King William I, the first king of the Netherlands and grand duke of Luxembourg, as part of a collection later transferred to what is now the Museum of Ethnology.

When the Netherlands recognised Indonesia’s independence in 1949, it was agreed that Diponegoro’s belongings would be returned. In 1968 a cultural treaty was signed and in 1975 items due to be repatriated were listed. But when Diponegoro’s saddle, spear and parasol were sent back, the kris was not.

It was only on the discovery of a series of secret memos, and their inclusion in a book by an art historian, Jos van Beurden, that the issue of the kris was raised once again.

It emerged that in 1983 the then Dutch ambassador in Jakarta, Lodewijk van Gorkom, had informed the foreign ministry that “confidential sources” had advised him that the dagger was hidden in the cellar of the Rijksmuseum in Amsterdam. Van Gorkom’s suggestion that it be returned was ignored.

His successor as ambassador Frans van Dongen had then written in 1985 to Pieter Pott, the director of the National Museum of Ethnology, saying he believed further efforts should be put into finding the dagger to mark the 40th anniversary of Indonesia’s independence. Van Dongen was said to have received a note from Pott that suggested the kris was in his museum but that its return was undesirable.

Pott was mistaken in his identification of Diponegoro’s weapon. But after publication of Van Beurden’s book, Treasure in Trusted Hands, outside experts were brought in by the Museum of Ethnology for a thorough investigation. Eight daggers were found that matched the description of Diponegoro’s dagger, and further work allowed the researchers to identify the true kris.

Van Beurden said the kris’s disappearance over decades was down to a mixture of lack of organisation and an unwillingness to hand treasures back to the Indonesians. “But that is changing now among the museums,” he said.

The dagger will be put on show in an exhibition at Indonesia’s National Museum in Jakarta.

The Bronbeek Museum of Colonial History in Arnhem believes it may also have one of Diponegoro’s belongings, a bridle belonging to a saddle already returned to Indonesia.

The museum’s director, Pauljac Verhoeven, said the item had an archive number attached to it that linked with the saddle, and further investigations were taking place. “We can’t yet establish whether it is,” he said. “It is just a small part but if we find out, we will return it.”