It's untrue to say that they're all polytheistic.
The most important difference is that Hinduism is polytheistic.
There were several polytheistic, non-Christian religions before Christianity. These would count as "pagan".
A number of religions developed out of Christianity. The most important of these is Islam.
The most important factor which has been ascribed to people converting to Christianity was the promise of salvation in the afterlife. Roman religion and other polytheistic religions just said that after death people went to the underworld, but did not have much to say about the afterlife. Moreover, Christ was a compassionate figure who cared about humanity, whereas the gods of the polytheistic religions did not care much about humanity. Another factor was that the Christians had a missionary zeal and actively pursued converting people, whereas there was no such missionary fervour in other religions.
Most religions are polytheistic, monotheistic, or particularistic. Some monotheistic religions are particularistic as are polytheistic. There are no religions that are all three.
Islam & Christianity are two important African religions. (:
The religions in Egypt at the moment is Islam and Christianity. These religions are not connected to the religions of ancient egypt.
Islam & Christianity.
You say "the" polytheistic religion; however, you should note that there is not ONE polytheistic religion, but several different such religions. The only thing all have in common is that they believe in several gods.
There are no distinctly European characteristics of any of these religions. Judaism, Christianity, and Islam are the same general faiths regardless of where the practitioner lives. There are certainly localized cultural flavors to these religions in Europe, such as cuisine or general style of dress, but the root of these religions is the same.
Islam and Christianity
It is one of the world's great religions.