Reading Simon Schama's Hang-Ups, subtitled Essays on Paintings (Mostly), I'm impressed by his perceptive, generous and undogmatic views of artists as various as Vermeer and Chaime Soutine. As you would expect of an historian, his biographical sketches of the painters he reviews are excellent; perhaps less expected is the brilliance of his insights into the works; but the best essay in the collection that I've read so far is about Christopher Columbus. Written for the quincentennial in 1992, this surveys most of the recent literature on the navigator and revises it in terms of another view entirely: not a man with a vision of a New World at all, but a religious maniac obsessed, like the Crusaders, with the recovery of Jerusalem and the re-occupation of the Holy Land. Schama suggests Colón's quest for the riches of the East was never for its own sake but in order to undertake yet another crusade into Palestine. He wanted to re-build the Tomb of Solomon and sought jewels and gold for the specific purpose of adorning the sarcophagus. His religious obsession extended to himself and particularly to his name: he was the Christ seeker, the populator who would bring the heathen into the fold of the Church, and the Dove of Peace foretold in the Bible. He also thought his Voyages would inaugurate the Last Days. As he wrote to Ferdinand and Isabella in 1500, in the Letter which acts as a preface to his Book of Prophecies: I was not aided by intelligence, by mathematics or by maps. It was simply the fulfillment of what Isaiah had prophesied.

There's a resonance here with another book I picked up at the weekend - literally, it was in a pile outside the Summer Hill St. Vincent's de Paul and I was unable to resist taking it, along with a copy of Gray's Anatomy - that is, a Modern Library edition of Plutarch's Lives in a version overseen and perhaps partly translated by Dryden, then revised by the Victorian Arthur Hugh Clough. I turned straight to the Life of Alexander who was, like Colón, convinced he was the instrument of destiny and tended to regard his own acts, self-consciously, as expressions of divine fate. His father, he believed, was not Philip of Macedonia but a god, variously identified as Apollo, Jupiter and Ammon; the snake found sleeping in his mother Olympias's bed was said to be an avatar of this god, thereby abating Philip's passion for his wife. Alexander's famous visit to the Temple of Ammon in Egypt just after he had laid out the City of Alexandria was to ask a direct question about his paternity of the god; and he swore never to divulge the answer he received to anyone but his mother. Because of his early death in Iraq, was it? (I haven't got to that bit yet) I don't think he ever did.

These religious madmen who attempt and sometimes succeed in conquering the world might seem quaint and somehow faraway, if it weren't the case that they are still very much with us ...