The Business of War in Europe, 1000–1600 65extensive expansion occurred east of the Elbe where, by the mid
thirteenth century, German knights and settlers extended their sway
across the north European plain as far as Prussia. Further east and
north along the Baltic coast German knights imposed their rule on
native peasantries all the way to the Gulf of Finland in the same
century. On other frontiers Latin Christians also exhibited remarkable
aggressiveness: in Spain and southern Italy at the expense of Moslems
and Byzantines and, most spectacularly of all, in the distant Levant,
where the First Crusade (1096–99) carried an army of knights all the
way to Jerusalem.
By 1300, however, this sort of expansion had reached its limits.
Climatic obstacles set bounds to the indefinite extension of the fields,
cultivated by the moldboard plow, that provided the basic foodstuffs
supporting western European society. When seed-harvest ratios sank
too low, as happened in arid parts of Spain or in the cold chill of
northern and eastern Europe, the heavy plow and the draft animals
required to drive it through the soil had to give way to cheaper ag
ricultural techniques. Along the same borderlands the relatively dense
settlement that the moldboard plow could sustain yielded to more
thinly populated landscapes in which pastoralism, hunting, gathering,
and fishing played a more important part than they did in the heartland
of Latin Christendom. Wherever knightly conquests outran the mold
board plow, social patterns differed from those of the west European
heartlands. The resulting political regimes were often unstable and
short-lived, as in the Levant where the crusading states disappeared
after 1291, or in the Balkans, where Latin dominion, dating from the
Fourth Crusade (1204), was largely supplanted by local dynasts as
early as 1261. In Spain and Ireland, on the contrary, and along the east
coast of the Baltic, conquest societies became enduring marginalia to
the main body of Latin Christendom. Similarly, in Poland, Bohemia,
and Hungary, kingdoms that consolidated around the effort needed to
repel German knights took a form divergent from, yet closely related
to, the knight and peasant pattern of western Europe.^3
Pioneering the Business of War in Northern ItalyThe military expansion of Latin Christendom in the eleventh century
was accompanied by an expansion of the scope for market behavior.
- Light cavalry and small scratch plows were cheaper than their west European
equivalents and fitted an environment in which seed-harvest ratios were lower than in
the more fertile west. The firmness of connection between lord and peasant was less in