Harry found himself hoping that Colon would lose his argument yet again. For if Colon by some chance swayed de Santangel, Harry knew that he was going to have to stand on his feet and shout Colon down, betraying years of effort by himself and his friends. Harry prayed that this convoluted dilemma could be resolved in some way that spared him making such a dreadful decision.

Without preamble Colon began to speak. It was a case he had set out many times before, and he told it clearly, with a deep, strong voice. But his tone was laced with impatience that he was forced to go through all this again, and his Spanish was poor, his Italian accent thick, and he stumbled over his words.

He began by quoting the authorities of antiquity. He leaned heavily on the great Ptolemy, who in the second century had presented a clear and consistent model of the world, around which the sun and stars rotated on crystal spheres. Colon knew Ptolemy through a three-centuries-old Latin translation of a book called the Almagest that had been preserved by the Arabs.

He referred too to the work of Pope Pius II, who before his elevation had written a book developing Ptolemy’s ideas, and a cardinal called Pierre d’Ailly whose Image of the World had presented strong views on the relative sizes of Asia and the Ocean Sea. He read extracts from Roger Bacon’s Opus Majus, which was a synthesis of Ptolemy’s vision with more recent work by Christian and Muslim geographers. Bacon argued that there was no significant land mass to be found save those already known: Asia, Africa and Europe.

Ferron scowled as Grace’s own engineer was quoted against her case.

Summing up these ideas, Colon presented a map drawn for him by one Martin Behaim, with a relatively narrow Ocean Sea and only a scattering of islands between Europe and Asia. If Colon’s arguments were correct then a voyage west across the Ocean Sea to the riches of the east, thus closing a circle around the curve of the earth, ought to be a trivial matter.

Colon was interrupted by a weary-looking geographer from Talavera’s party, who presented rebuttals he had been forced to make many times before. All this was supposition, he said, addressing de Santangel. ‘Nobody would argue with the bulk of Ptolemy’s ideas, so lucidly set down in a greater age than this, and preserved through the ignorant copying-down of the Arabs. Of course the earth sits at the centre of the universe; that much is obvious to a child.