In the large parchment letter, hung with over 80 pendant seals attached with red silk ribbon, they alluded to the "extreme remedies" they could pursue if their request were refused.

The letter, which preceded Henry's divorce from Catherine of Aragon and his rejection of the pope's authority, is one of 100 documents that have been released from the Vatican Secret Archives for display in Rome's Capitoline museums, the first time they have been allowed outside the Vatican City.

A 60 metre parchment scroll documenting proceedings of the trial of the Knights Templar medieval Christian military order, accused of heresy and sexual misconduct, is partially rolled out in one room of the museums, alongside secret manuscripts, letters and codices.

A register containing the excommunication of 16th century German reformer Martin Luther, and a report on the trial of Italian astronomer Galileo Galilei, who was condemned by the Inquisition for asserting that the Earth revolved around the Sun, are also on show.

Archivist Pier Paolo Piergentili said this was the first time in the archive's 400 year history that it was opening up a selection of documents for public display.

"The aim is to physically show the sources of history, and make available the documents that have created history in Europe, and not only Europe," he said.

Documents in the Vatican Secret Archives span the 8th to the 20th century and are stored on 85km of shelving in different sites within the sovereign state. Part of the collection is open for researchers upon request.

Founded by Pope Paul V in 1612, the archives contain all deeds and documents pertaining to the government of the Church.

The exhibition "Lux in Arcana: The Vatican Secret Archive Reveals Itself", running from March until September, aims also to demystify the Church's records.

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