I do not see a reason to discuss beliefs on internet. What do you people ned to prove? Or do you need permision to worship either paganism or christianity? People should keep it for themselves and that is it.

No, I dont discuss religious beliefs. I was discussing history. If I remember correctly, you are/were student of History.

We can philosophize about it till the morning, but It's just plane wrong to think that the Romans and the Slavs dealt and felt about their religions in same manner.

Who claimed so? I just said that terms polytheism and paganism are interchangable. Thats more etymology than philosophising. Ancient Slavic religion was falling under definition of polytheism. Not that all kinds of polytheism are same.

In theory, Christianity, Islam and Judaism are very similar monotheistic religions, but are they the same?

They are verry different on theoretical level, I would say, even more than on practical. (There are radical disagreements on matter of teaching, I meant that), but to return it on topic, they are all classified as monotheism, ie they worship one God, you could go even further and classified all three under category of Abrhamic faiths, ie they all claim inheritance of Abraham.