So early as under Casimir, the son of Jagello, the Polish language began to be employed as the language of the court.  Under his grandson Sigismund Augustus, the public laws and decrees were promulgated in the vernacular tongue of the country.  But a language which thus issued from the court, was necessarily also dependent on the changes of the court.  The influence of the French prince, Henry of Valois, successor of Sigismund Augustus, could not be considerable, as he occupied the throne only two months.  But Stephen Bathory, prince of Transylvania, the brother-in-law of Sigismund Augustus, who was elected after Henry of Valois had deserted the country, was as a foreigner in the habit of interspersing his conversation and writings with Latin words, when the proper Polish words, of which language he had only an imperfect knowledge, did not occur to him.  It is hardly credible that such a habit, or rather the imitation of it among his courtiers, could have had any influence on a language already so well established and cultivated, as the Polish idiom was at the close of the sixteenth century.  The Polish literary historians, however, ascribe to Bathory’s influence the fashion, which began at this time to prevail, of debasing the purity of the Polish language by an intermixture of Latin words and phrases.[23]

Although the Polish literature acquired during this period a kind of universality, and there were few departments of science, familiar to that age, which were not to some extent cultivated in it, yet it owes its principal lustre to the contributions made in it to history, poetry and rhetoric.  The didactic style did not reach the perfection of the historical; nor did Polish literature acquire any wide domain in purely scientific productions.  In accordance with the national tendency, the mass of distinguished talents was devoted to those interests, which yield an immediate profit in life, or which are themselves rather the results of empirical knowledge, than of abstract contemplation, viz. to politics, to eloquence, and to poetry, in so far as this latter is considered not as a creative power, but as the most appropriate means for expressing and describing the emotions, passions, and actions of man.  There have however always been not a few gifted Poles, who have cultivated the field of science for its own sake, without reference to the practical importance of their labours; and there are more especially at the present time many distinguished names among the Polish mathematicians, natural philosophers, and chemists.  In Copernicus himself, born indeed of parents of German extraction, and in a city (Thorn) mostly inhabited by German colonists, but also born a Polish subject and educated in a Polish university, Poland and Germany seem to have equal rights.[24]