The last chapter described some of the revolutionary changes marking the end of the medieval world. In warfare, the most obvious transformations were the creation of standing armies in which infantry replaced cavalry as the dominant element and the professionalisation of artillery as processes begun in the middle of the fifteenth century took root. In terms of engineering, this continued to have an effect, with gunnery becoming a separate specialism, although – as we will see – the application of scientific knowledge to the skills of the artilleryman took a great deal longer to register. The acceptance that a geometric approach to fortress design also required the integration of both the defensive and offensive use of modern artillery continued to evolve before finally arriving at commonly agreed principles, but not before the middle of the sixteenth century, and throughout this time called upon parallel progress in military engineering aiming to overcome such defences.

In Europe, warfare was more or less continuous in the first half of the new century. Successive kings of France initiated campaign after campaign to make good their claims to the inheritance of the kingdom of Naples and the duchy of Milan, starting with the irresistible invasion of a large army under Charles VIII in 1494. The small city states of Italy, even with their advanced systems of fortifications, proved powerless and it took military intervention from Spain to throw out the invaders. This led to more than sixty years of conflict involving France, Spain, the Holy Roman emperor (the Habsburg Maximilian, succeeded in 1519 by Charles V who combined rule of Spain, the empire and the Low Countries), the papacy and all the states of Italy, including Venice, in a patchwork of changing alliances. Peace was not made until 1559. Charles V was also engaged in conflict with German states that embraced Lutheranism from 1517, and faced the continuing expansion into Europe of the Ottoman Turks (who conquered Hungary in 1526 and besieged Vienna in 1529), while Henry VIII of England (1509–47) had broken with his father’s prudent abstention from military adventure to demand his moments of glory.