The correct answer is that the information in the map shows that the population in most European countries in 1600 was about equally Catholic and Protestant.
The map shows that the Protestant Reformation of the previous century had expanded throughout Northern Europe, where the different Protestant branches had become the majority religion.
In contrast, Catholicism had asserted itself as the predominant religion in southern Europe, with the exception of Ireland.
In synthesis, the map shows how as much the catholicism as the Protestantism had been divided in equal parts the amount of Christian faithfuls of Europe in the 17th century.
