Fortune is a River: Leonardo da Vinci and Niccolo Machiavelli's Magnificent Dream to Change the Course of Florentine History (review)

Roger Masters’s picturesque title draws us into a fascinating account of a dramatic moment in the history of Renaissance Italy, when two of its most brilliant and most enigmatic figures embarked on a very ambitious engineering project: the diversion of the river Arno above Pisa, so as to deprive that city of its maritime commerce. Leonardo indeed was to devise a much grander scheme; a canal to take the Arno’s water far out of its course. Just below Florence it would swing away to the northwest and then south again, to form a navigable channel that would allow shipping to sail up the river as far as Florence itself.

Although Leonardo may have intended to explain this idea to the responsible authorities, and even drew up maps to assist him, it was certainly not within the realm of possibility for a republic that could not even bring to heel its recalcitrant neighbor. The original program to turn the Arno aside not too far from the sea was perhaps just about feasible. Certainly the Florentine government was persuaded so. However, it did not succeed, and Pisa was eventually forced to surrender by more conventional military means.

The administration of the original plan was supervised and championed by Machiavelli. Whether the diversion would really have changed the course of Florentine history is doubtful. Pisa fell anyway, and the Florentine republic itself collapsed soon after. Cities that were rich but not powerful were, as Machiavelli realized, always at the mercy of kings who ruled whole nations and could command great armies. However, Masters reconstructs for us the course of events—month by month, at times almost day by day—when the project still seemed attainable and decisive. This is preceded by an account of his heroes’ lives before they came together, which, he suggests, occurred while Leonardo was employed as an engineering consultant for that most celebrated of papal bastards, Cesare Borgia, at Imola, where he made a map that surpassed in accuracy any town map of his own day, and for long after. Moreover, Masters thinks, the Florentine secretary may even have learned of Leonardo’s ideas on river diversion for irrigation, drainage, and transport at this stage.

Eventually Pisa declined as a port, as ships grew too large for the river to accommodate them. It is hard to see how Florence could have ever been a rival. Not far to the west of the city the Arno forms a number of bends and passes over rapids as it skirts the southern spurs of the hills called Monte Albano. Leonardo’s solution was to take the river’s water so far to the north as to be quite impractical. Perhaps Machiavelli’s dream of building a citizen army to defend Florence instead of using costly and unreliable mercenaries was equally utopian; when he did succeed in getting his proposal adopted he had to recruit peasants from the countryside, who were definitely not citizens and who served out of compulsion, or for pay.

Leonardo is an even more remarkable character than Machiavelli, but Masters seems a little weaker on him. In an otherwise excellent bibliography, the section on Leonardo’s “scientific contributions” includes few items less than thirty years old and little on Leonardo specifically as an engineer. Readers of Technology and Culture may be puzzled that Masters appears to have so little sense of Leonardo’s context; no mention of Taccola, Francesco di Giorgio, even Alberti. The most Masters can say is that “there were other artists (like Brunelleschi) interested in a scientific approach to perspective and anatomy” (p. 30). It is true that Leonardo’s investigation of nature was far more profound, and went, as Masters says, “in more varied directions.” Yet there was a long tradition of mechanical innovation and hydraulic engineering...