in trouble with the religious authorities,
and in 1544 he was arrested, tried, con-
victed, and briefly imprisoned on a charge
of heresy.
In 1552 Mercator moved to Duisburg,
in the Germany duchy of Cleves, where he
was appointed a professor of mathematics
and also became a land surveyor. In Duis-
burg, where he remained for the rest of
his life, he helped to found a grammar
school and continued his work in cartog-
raphy. After publishing a map of Europe
in 1554 and then several other local maps
of Britain and the European continent, his
reputation spread. He also developed a
new method of producing globes, in which
he pasted on the sphere printed maps that
were cut to fit by tapering their edges to-
ward the top and bottom.
Mercator was appointed by the Duke
of Cleves as an official court cartographer.
He perfected his system of marking paral-
lel lines on a map to indicate degrees of
longitude that could be applied to naviga-
tion charts and allow ship captains to
more accurately follow their course at sea.
He first used this system on a map of the
world he completed in 1569. In the 1570s
he began producing an atlas, a collection
that included the maps of the ancient
Greek astronomer Ptolemy as well as his
own maps covering France, Germany, Italy,
the Netherlands, eastern Europe, Greece,
and the British Isles. This work, which he
completed over the span of more than
twenty years, was finally published by his
son after his death.
mercenaries ......................................
Warfare went through an important
change in the late Middle Ages. Once the
domain of mounted knights who fought
in the service of their feudal overlords,
war became a matter for professional mer-
cenary armies that fought for powerful
kings. The mounted knight was no match
for masses of archers and crossbowmen,
who dominated the battlefield during the
Hundred Years’ War in France. This war,
which dragged on for generations until
the final defeat of the English in the 1450s,
demanded permanent armies in the field.
A permanent force was an impossibility
under a feudal system that demanded only
forty days of annual service from a king’s
vassals.
At the same time, the economy of Eu-
rope was expanding through better trans-
portation and communications, and the
new international banking system relied
on credit, money, and bills of exchange.
This made it possible for rulers to borrow
and to hire mercenaries to fight their
battles. Mercenaries could take the field
for as long as they were paid, allowing
kings and princes to mount long cam-
paigns against their rivals and undertake
sieges of enemy fortresses. The system had
its roots in the practice of scutage, or pay-
ment by a vassal in lieu of military service.
The payment of scutage allowed feudal
lords to hire professional soldiers, who
trained from a young age in the military
arts and often proved more able than he-
reditary knights who simply fought out of
traditional obligation.
Mercenaries came from all corners of
Europe, but they were especially numerous
in Switzerland, then a poor land where
young men looked elsewhere for opportu-
nity. The Swiss infantry enjoyed a reputa-
tion as skilled fighters, well disciplined and
well armed with fearsome halberds, which
could kill an armored knight at a single
blow. Mercenary captains assembled small
armies, drilling them relentlessly with for-
mation and fighting tactics, in which in-
fantry, archers, and cavalry were carefully
coordinated.mercenaries