downwind. It was virtually useless in other conditions.
Many of the smaller craft were therefore assisted by
oars or sweeps and could penetrate coastal estuaries as
had the Viking longships on which they were often
modeled.
In the Mediterranean, many ships carried the trian-
gular lateen sail, invented by Arab sailors in the Indian
Ocean and introduced to Europe by the Byzantine
Greeks. It permitted a ship to sail close to the wind and
was used on both galleys and the larger round ships
that were propelled by sails alone. The round ship,
broad-beamed and steered by long oars slung from the
stern quarters, was sturdy, capacious, and very slow. It
was the bulk carrier of the Middle Ages. Galleys were
still used for warfare and for cargos that were either
perishable or whose value-to-weight ratio was high.
Fast and maneuverable, they were as dependent on the
land as their ancient counterparts and too fragile for ex-
tensive use in the open Atlantic.
These generalizations, referring as they do to a pe-
riod of more than a thousand years, imply that little
technological change was evident in the Middle Ages.
This is not true, but by modern standards the rate of
change was relatively slow. The medieval economy re-
mained basically agricultural, with more than 90 percent
of the population directly engaged in the production of
food. Cash remained scarce, and the surplus of goods
and services beyond those needed for mere subsistence
was small. The accumulation of capital for investment in
new technologies was therefore difficult, and the de-
mand for innovations was slight because most people
had little or no discretionary income.The Agricultural Revolution of the
Eleventh and Twelfth Centuries
The rate of technological change, though slow by
modern standards, did not prevent Europe from dou-
bling its agricultural productivity between the years
1000 and 1250. Population doubled as well (see table
10.1). Climatological evidence suggests that a general
warming trend extended the growing season and per-
mitted the extension of cultivation to more northern re-
gions and to higher elevations. No major famines
occurred during this period, and crises of subsistence
tended to be local and of short duration. However,
changes in the climate alone cannot account for such
an unprecedented expansion.
The return of more-or-less settled conditions after
the great raids of the ninth and tenth centuries was
certainly a factor. The annual loss of food, tools, live-
stock, and seed grain to the marauders had been sub-
stantial. When augmented by forced requisitions and
by the depredations of local feudatories its impact on
subsistence must have been great. A number of techni-
cal innovations increased productivity, though some
were dependent upon a preexistent improvement in
conditions for their success. The extension of the
three-field system through much of northwest Europe
is an example. By leaving only one-third of the land
fallow in any given year, as opposed to half under the
earlier system, peasants were able to increase their
yields without seriously diminishing the fertility of
their land. They typically planted a winter crop in one178 Chapter 10Illustration 10.1
Unloading Wine at Paris.The
commercial revolution began with the
bulk trade in such agricultural commodi-
ties as wine. Wine was always shipped in
barrels, as bottling was unknown. Given
the condition of the roads, shipping by
river boat was almost always cheaper
and faster. Here boatmen are delivering
their casks at the port of Paris on the
river Seine.