Orthodox Muslims believe that this ancient Islamic text is the unchanging Word of God. One scholar is daring to question it

A German academic fears a violent backlash from orthodox Muslims because of his "blasphemous" theory that the Koran has been changed and revised. Such a backlash is not to be taken lightly; the Salman Rushdie affair is a solemn reminder of the power of an angry Muslim community. After the author wrote his novel Satanic Verses, which was considered by Muslims to be blasphemous, a fatwa , or religious decree, was pronounced against him in 1989 that left him fearing for his life. Rushdie has only recently reappeared in public after nearly 10 years in hiding.

According to Muslim belief, the Koran is the eternal, unaltered Word of God, which has remained the same for 14 centuries.

But Dr Gerd R Puin, a renowned Islamicist at Saarland University, Germany, says it is not one single work that has survived unchanged through the centuries. It may include stories that were written before the prophet Mohammed began his ministry and which have subsequently been rewritten.

Puin's conclusions have sparked angry reactions from orthodox Muslims. "They've said I'm not really the scholar to make any remarks on these manuscripts," he said.

The semitic philologist, who specialises in Arabic calligraphy and Koranic palaeography, has been studying Sa'na manuscripts, ancient versions of the Koran discovered in Sa'na, the capital of Yemen.

So controversial are his findings that the Yemeni authorities have denied him further access to the manuscripts.

He says they shed new light on the early development of the Koran as a book with a "textual history", which contradicts the fundamental Muslim belief that it is the unchanging Word of God.

Any questioning of the authenticity of the Koranic text as the Word of God can expect a hostile reaction. The fatwa , or death sentence, was issued against Rushdie for hinting in Satanic Verses that the Koran may include verses from other sources - chiefly Satan.

Academics offering radical interpretations of the Koran put their lives at risk. In 1990, Dr Nasr Abu Zaid, formerly a lecturer in Koranic Studies at Cairo University, provoked a national outcry in Egypt over his book The Concept of the Text. There were death threats from Muslim extremists, general public harassment, and in 1995 he was branded an apostate by Egypt's highest court. The court forced him to divorce his wife because under Islamic law, marriage between an apostate and a Muslim is forbidden.

Zaid's proposal was arguably less radical than Puin's. Zaid's book argued that "the Koran is a literary text, and the only way to understand, explain, and analyse it is through a literary approach". A Muslim, Zaid remained in Egypt for a time to refute the apostasy charges, but fled with his wife to Holland in the face of increasing death threats.

Puin believes that he will not receive the same reaction, because unlike Zaid or Rushdie he does not have a Muslim name.

His claim that the Koran has changed since its supposed standardisation, and that pre-Islamic texts have crept in, would nonetheless be regarded as highly blasphemous by Muslims. He has not yet written a book on his radical findings, but says it is "a goal to achieve" in the near future.

Dr Tarif Khalidi, lecturer in Islamic Studies at Cambridge University, warns that the book may generate a controversy similar to Satanic Verses. "If Dr Puin's views are taken up and trumpeted in the media, and if you don't have many Muslims being rational about it, then all hell may break loose."

Khalidi fears Muslims will not accept Puin's work on the Sa'na manuscripts as having been done with academic objectivity, but see it as a deliberate "attack on the integrity of the Koranic text".

The manuscripts, thought to be the oldest surviving copies of the Koran, were discovered in the ancient Great Mosque of Sa'na in 1972, when the building was being restored after heavy rainfall, hidden in the loft in a bundle of old parchment and paper documents. They were nearly thrown away by the builders, but were spotted by Qadhi Isma'il al-Akwa, then president of the Yemeni Antiquities Authority, who saw their importance and sought international assistance to preserve and examine them.

Al-Akwa managed to interest Puin, who was visiting Yemen for research purposes in 1979. Puin in turn persuaded the German government to organise and fund a restoration project. The restoration revealed that some of the parchment pages dated from the seventh and eighth centuries, the crucial first two centuries of Islam, from which very few manuscripts have survived.

Until now, there were three ancient copies of the Koran. One copy in the Library of Tashkent in Uzbekistan, and another in the Topkapi Museum in Istanbul, Turkey, date from the eighth century. A copy preserved in the British Library in London, known as the Ma'il manuscript, dates from the late seventh century. But the Sa'na manuscripts are even older. Moreover, the Sa'na manuscripts are written in a script that originates from the Hijaz - the region of Arabia where the prophet Mohammed lived, which makes them not only the oldest to have survived, but one of the earliest copies of the Koran ever.

Puin noticed minor textual variations, unconventional ordering of the chapters (surahs), as well as rare styles of orthography. Then he noticed that the sheets were palimpsests - manuscripts with versions written even earlier that had been washed off or erased.

These findings led Dr Puin to assert that the Koran had undergone a textual evolution. In other words, the copy of the Koran that we have is not the one believed to have been revealed to the prophet.

This is something that Muslims would find offensive.The idea that the Koran is the literal Word of God, unchanging and permanent, is crucial to Islam.The traditional Muslim view holds that the Koran was revealed to Mohammed by God in fragments between 610 and 632 AD. The revealed verses were "recorded on palm leaves and flat stones and in the hearts of men [meaning memorised]," and remained in this state during the prophet's lifetime.

About 29 years after Mohammed's death during the rule of the third Muslim caliph, Uthman, a standard copy of the Koran in a book form, was made, because already divergent readings and copies were circulating in the growing Islamic empire. This Uthmanic recension, according to the Muslim view, was produced with meticulous care, based on earlier copies of the Koran made according to the instructions of the prophet.

Orthodox Muslims insist that no changes have occurred to the Koran since the Uthmanic recension. But this view is challenged by the Sa'na manuscripts, which date from shortly after the Uthmanic recension.

"There are dialectal and phonetical variations that don't make any sense in the text", says Puin. "The Arabic script is very defective - even more so in the early stages of its literature."

Like other early Arabic literature, the Sa'na Koran was written without any diacritical marks, vowel symbols or any guide to how it should be read, says Puin. "The text was written so defectively that it can be read in a perfect way only if you have a strong oral tradition." The Sa'na text, just like other early Korans, was a guide to those who knew it already by memory, he says. Those that were unfamiliar with the Koran would read it differently because there were no diacritical and vowel symbols.

As years went by, the correct reading of the Koran became less clear, he says. People made changes to make sense of the text. Puin gives as example Hajjaj bin Yusuf, governor of Iraq from 694-714 AD, who "was proud of inserting more than 1,000 alifs [first letter of the Arabic alphabet] in the Koranic text".

Professor Allen Jones, lecturer in Koranic Studies at Oxford University, agrees.

"Hajjaj is also responsible for putting the diacritical marks in the Koran. His changes are a defining moment in the history of the Koran".

After Hajjaj's changes in around the 700s, "the Koranic text became pretty stable", he says.

Puin accepts this up to a point, but says that certain words and pronunciations were standardised in the ninth century. He says the Uthmanic text was the skeleton upon which "many layers of interpretation were added" - causing the text to change.

This is blasphemy, according to orthodox Muslims, and is not entirely accepted by other academics.

Jones admits there have been "trifling" changes made to the Uthmanic recension. Khalidi says the traditional Muslim account of the Koran's development is still more or less true. "I haven't yet seen anything to radically alter my view," he says.

He believes that the Sa'na Koran could just be a bad copy that was being used by people to whom the Uthmanic text had not reached yet. "It's not inconceivable that after the promulgation of the Uthmanic text, it took a long time to filter down."

Puin's other radical theory is that pre-Islamic sources have entered the Koran. He argues that two tribes it mentions, As-Sahab-ar-Rass (Companions of the Well) and the As- Sahab-al-Aiqa (Companions of the Thorny Bushes) are not part of the Arab tradition, and the people of Mohammed's time certainly did not know about them.

"These are very unspecific names, whereas other tribes are specifically mentioned," said Dr Puin.

His researches have shown that the ar-Rass lived in pre-Islamic Lebanon and the al-Aiqa in the Aswan region of Egypt around 150AD, according to the Atlas of Ptolemy. He argues that pre-Islamic sources entered the Koran, presumably when the growing Islamic empire came into contact with those regions and sources.

Khalidi says finding pre-Islamic registers in the Koran does not discredit the Muslim belief in any way, because it does not threaten the integrity of the Koran. "The Koran was revealed at a particular time in the vocabulary of the age", he says.

Puin also questions another sacred belief that Muslims hold about the Koran, that it was written in the purest Arabic. He has found many words of foreign origin in the text, including the word "Koran" itself. Muslim scholars explain the "Koran" to mean recitation, but Puin argues that it is actually derived from an Aramaic word, qariyun, meaning a lectionary of scripture portions appointed to be read at divine service. He says the Koran contains most of the biblical stories but in a shorter form and is "a summary of the Bible to be read in service".

Orthodox Muslims have always held that the Koran is a scripture in its own right, and never a shortened version of the Bible, even if both texts contain the same prophetic tradition.

Khalidi says he is weary of constant attempts by western Islamicists to analyse the Koran in a parallel way to the Bible. Puin, however, sees the need for a "scientific text" of the Koran, and this is what he intends to achieve. He says that Muslims believe that "the Koran has been worked on a thousand years ago" and "is not a topic anymore".

Not all Muslim reaction to him has been hostile. Salim Abdullah, director of the German Islamic Archives, affiliated to the powerful pan-Islamic Muslim World League, has given him a positive response.

"He asked me if I could give him the permission to publish one of my articles on the Sa'na manuscripts", said Puin. Warned of the possible controversy it could raise, he replied: "I am longing for this kind of discussion on this topic."