The game map shows the main area of the Duchy of Milan and parts of the surrounding countries at the beginning of the 16th century.
It describes the Po Valley from the city of Asti to the city of Parma in the west-east direction and from Alps to Appennines in the north-south.
We chose two different scales horizontally (1:200000) and vertically (1:240000) in order to preserve the distances in hexes in these directions. The top of the map deviates from north by some degrees.

In order to define the features of the territory, we compared the today's
military maps with maps of the past centuries and other bibliographic sources.
Even if military cartography was at its very beginning at the time of the Italian Wars, we consider that most of the territory should not have changed so much until the Napoleonic era. So we examined some hundred maps and town plans from 16th up to 18th century, and in particular we used a very accurate map of the Austrian Lombardy made by the astronomers of Brera (Milan) at the end of the 18th century.

Another extremely interesting source was a manuscript written for military purposes at the time of the Italian Wars by a nobleman of Lodi for King Francis I of France. It is now preserved at the National Library of Brera, Milan (ref. A. Vignati, Itinerario Militare, AG XI 42).
In this book, cities and towns and almost every village in northern Italy are described, together with the roads connecting them and the related distances, and the number of horses that could have been supposedly housed in it. According to this manuscript, we discovered that even the majority of the small villages and big farm houses ("cascine") that existed in the 16th century, do still exist today, while few ones have been added since then.

The demography of the period is not very well known: it was based mostly on families (or "fuochi") and performed for ecclesiastic and fiscal purposes.
Emperor Charles V ordered to take a census of the Duchy of Milan in 1545-1546, but its results are not considered very reliable by the historians. To get an idea, we report here a list of the population of many of the largest cities on the map in year 1500:

Asti	8000
Bergamo	15000
Brescia	48000
Como	10000
Cremona	40000
Milano	100000
Parma	18000
Pavia	16000
Piacenza	25000

(ref. Carlo M. Cipolla, "Before the industrial revolution : European society and economy, 1000-1700").

It has to be remembered that the Italian population was severely affected by wars and related events like famine or plague during the Italian Wars.
As example, the city of Treviglio counted about 13000 people in year 1499,
while it did not reach 4500 souls in 1529, after a sack and many hand changing.

In general, cities were surrounded by a wall and contained also one or more strong castles ("cittadella"), usually connected to the wall; smaller castles afforded defense to town and villages. Actually, so many small or not so small castles were scattered on the countryside that almost each hex on the map should contain one. On the other hand, most of these castles were ineffective, due to loss of maintenance and to the recent development of artillery. It was indeed during the Italian Wars that was developed a new
kind of fortress, with low and thick walls, armed with guns and defended by bastions. Known as the "trace italienne", it will become common all over Europe and overseas in the following centuries. In the map, we defined cities and town taking in account their relevance, population and level of fortification.

The road net in the game was defined cross-referencing the maps of today with the old ones and the references in the manuscript above. Again we observed that almost each hex should contain a road of some kind, while on the other hand, the road maintenance was so bad that in some occasion, in winter, it was impossible to move guns along roads. So again, we decided to represent only the major communication axis with some relevant (and used) alternative.

The Po river altered its course many times in the past centuries until it was
finally embanked. We described its lower course according to a map
drawn in 1583 by an engineer of Piacenza, named Bolzoni, and preserved
in the state archive of Parma. Again we checked that it is fairly consistent
with the manuscript.

River crossing was performed mainly by ford or ferries, while bridges of boats were available on the mayor roads and close to the cities. Stone bridges were rare and usually fortified. We detected a few only: the bridge on the Ticino river at Pavia and the bridge on the Adda river at Trezzo. A third one, at Bobbio, is not very relevant to the game.

Rice cultivation started in Lombardy in the 15th century and spread rapidly in the 16th century. However, the rice fields on the map represent the status of this cultivation at later times. So they comprises indeed not only the actual rice-fields, but also some other kind of terrain that was converted later to rice-field. We think that it should not induce too big mistakes in the terms of the game.
 
The authors wish to thank many people that helped in this very interesting and amusing work. First of all, we wish to thank the Prof. Pasquale Tucci
of the Astronomical Observatory of Brera, who lent us his copy of the map of the Austrian Lombardy. Then we thank Marco Galandra for his suggestions and information on the period, and a kindly visit to the battlefield of Pavia.
Finally, we wish to remember here some friends that supplied us with
maps, books, CDs and suggestions. In rigorous alphabetic order, namely,
Alessandro Albanese, Alessandro Beretta, Chiara Marmo, Andrea Mazzolini,
Giovanni Peroni and Livio Pinto.
Once more, thanks to you all.