From a position of almost total anonymity in the tenth century, there are records of the names of engineers, builders, master craftsmen and master miners in the twelfth. There is still no evidence that a separate category of military engineer was coming into existence, and there remain numerous accounts of events requiring engineering in which no engineer was named, but over the course of around 150 years between the middle of the eleventh and the end of the twelfth centuries a trend towards both the identification of individuals and a certain level of specialisation can be suggested that is not entirely due to the accidental survival of the records. In this chapter I will present the economic background, the possible relevance of advances in science and the evidence for technological improvement. I will then review what happened in actual campaigns and the role of the engineer within these contexts.

An Age Of Economic Growth – And Some Of Its Consequences

Underpinning these and many other important historical developments was a long period of economic growth rooted in a substantial increase in population, leading to extensive clearance of lands as well as the settlement of new territories – one feature of this period was a powerful drive eastwards by German rulers to take over the lands and peoples of the Slavs in what is now eastern Germany, as well as the establishment of new monarchical states in largely Slav lands such as Bohemia (which was part of the empire), Poland, and the western Balkans, and Magyar Hungary (which were not). It is not possible to more than guess at the size of medieval populations, based on very tenuous evidence, but it is generally accepted that in the tenth century Europe was a very empty continent by comparison with later ages and there was plenty of uncultivated land to spare. It has been argued that the return of (relative) stability following the ending of the Scandinavian, Magyar and North African raids that had caused disruption and insecurity in many areas, and the establishment of new political entities (which sometimes included the former invaders, as in Normandy and England) exercising control over their states, based in agriculturally fertile areas, encouraged the production of an economic surplus beyond what was required for subsistence.