I have finished 2 camapigns as the Polish on GA expert one starting in early & the other in high period. In both of the campaigns I had one steadfast ally who never ever attacked me even when I left completely undefended borders for long periods of time. The Hungarians became quite large in the early campaign they where at war with everyone & where excommunicated but they never attacked me. I always remained allied to them & they always choose me over any other faction, I was playing GA & only had a small empire. I even decided not to take Hungary(part of polish GA) from them as they had been nothin but nice to me