daughter of Louis of Hungaria. to the Lithuanian prince Jagiello, elected him King of Poland, and in this way realised a personal union between Poland and Lithuania. Lithuania proper, i.e. the Northern part of Jagiello's empire, which was still pagan, was baptized by the Poles, converted to the Roman Catholic religion and exposed to the influence of Pohsh civilisation. At a great meeting of Polish and Lithuanian nobles an Act of Brotherhood between the two countries was signed and a solemn oath taken by both parties. Thenceforth the hereditary grand dukes of Lithuania, of the House of Jagiello, were by principle elected to the Polish throne up to the reign of Sigismund Augustus, who died childless but during whose reign the Union of Lublin was concluded (1569), whereby the two countries were fused into one State and by virtue of which Lithuanian deputies began to be sent to the Polish Diet.
By the union with Lithuania the Polish State was more than doubled in territory and in population. That population was Polish neither by race nor by civilisation. In the north of the newly acquired country lived the Lithuanians, recently converted from paganism and still semi-barbarous. The southern and larger part of it was inhabited by West-Russian Slavs (White and Little Russians), Christians since the end of the tenth century, but belonging to the Eastern Church and to the Byzantine civilisation. The close union with Lithuania in the second half of the sixteenth century was bound to lower the general intellectual level of the Polish State. And after that time Poland was a very heterogeneous country in race, in language,
