[Sidenote: 1561] War with Sweden resulted from this but was settled by the cession of Esthonia to the Scandinavian power.
Internally, the vigorous Jagiello strengthened both the military and financial resources of his people.

To meet the constant inroads of the Tartars he established the Cossacks, a rough cavalry formed of the hunters, {140} fishers, and graziers of the Ukraine, quite analogous to the cowboys of the American Wild West.

From being a military body they developed into a state and nation that occupied a special position in Poland and then in Russia.

Sigismund's fiscal policy, by recovering control of the mint and putting the treasury into the hands of capable bankers, effectively provided for the economic life of the government.
[Sidenote: Reformation] Poland has generally been as open to the inroads of foreign ideas as to the attacks of enemies; a peculiar susceptibility to alien culture, due partly to the linguistic attainments of many educated Poles and partly to an independent, almost anarchical disposition, has made this nation receive from other lands more freely than it gives.

Every wave of new ideas innundates the low-lying plain of the Vistula.