I know that religion has a big role in this, but i want to know what are the relations between west and east Europe for ages and why the westerners are more developed then easterners. This from the point of view of historians.
This is a huge topic and there are very many good books to suggest. A standard text on economic development is Sylla and Toniolo's "Patterns of European Industrialization" which does focus a lot on post-1800 history but also gives a solid modern perspective on the very influential Alexander Gerschenkron's theories on economic development; Gerschenkron himself is a Ukrainian-American who is one of the foremost thinkers of the Austrian School of Economics. J.L. Van Zanden's "The long road to the industrial revolution" is also good; a bit more esoteric but broader in scope.
A more recent, less economic, and more readable history analyzing the impact of communism on Eastern Europe is "Cold War Europe: The Politics of a Contested Continent" by Mark S. Gilbert at Johns Hopkins.