As governor and viceroy of the Indies, Columbus imposed iron discipline on the first Spanish colony in the Americas, in what is now the Caribbean country of Dominican Republic. Punishments included cutting off people's ears and noses, parading women naked through the streets and selling them into slavery.

"Columbus' government was characterised by a form of tyranny," Consuelo Varela, a Spanish historian who has seen the document, told journalists.

One man caught stealing corn had his nose and ears cut off, was placed in shackles and was then auctioned off as a slave. A woman who dared to suggest that Columbus was of lowly birth was punished by his brother Bartolomé, who had also travelled to the Caribbean. She was stripped naked and paraded around the colony on the back of a mule.

"Bartolomé ordered that her tongue be cut out," said Ms Varela. "Christopher congratulated him for defending the family."

The evidence has been found in a previously lost report drawn up at the time for the Spanish monarchs as they became worried by growing rumours of Columbus' barbarity and avarice. The document was written by a member of an order of religious knights, the Order of Calatrava, who had been asked to investigate the allegations against Columbus by Queen Isabella and King Ferdinand, who ruled Spain together at the time.

The report, by Francisco de Bobadilla, lay undiscovered in a state archive in the Spanish city of Valladolid until last year. Bobadilla had already been named governor of the Indies, replacing Columbus, at the time of the report.

The 48-page document gathers evidence from Columbus' enemies and supporters of his seven-year reign. Ms Varela, one of the two Spanish historians to have studied the document, described life in the colony as "horrifying and hard".

Bobadilla collected the testimonies of 23 people who had seen or heard about the treatment meted out by Columbus and his brothers. "Even those who loved him had to admit the atrocities that had taken place," Ms Varela said.

Columbus and his brothers were forced to travel back to Spain. Columbus was in chains but, although he never recovered his titles, he was set free and allowed to sail back to the Caribbean.

"Columbus and his brothers come across in the text as tyrants," Ms Varela said. "Now one can understand why he was sacked and we can see that there were good reasons for doing so.

"The monarchs wanted someone who did not give them problems. Columbus did not solve problems, he created them."