"True representation and depiction of his highness1, the high-born prince and lord, Sir Bethlehem Gabor, Prince in Siebenbürgen2, together with a conversation between the latter and the religion3 - including the common estates of the country4 devoted to it - regarding the current war affairs."
1 literally Durchleuchtig means Enlightened or Light-imbued. It was used as an address for high aristocrats in German.
2 Siebenbürgen = Transsylvania in English
3 "the religion" probably refers to Protestantism
4 Landstände = Estates of the Country, an administrative structure specific to the German and German-influenced lands in central and eastern Europe. Basically they are representatives of the important local entities such as cities, towns, gentry, patricians, monasteries, etc. The common estates would then have been just the non-noble, non-clerical part of this.