The entire idea of the Trinity as being pagan is BOGUS.
The Father and Holy Spirit are clearly seen in the Old Testament.
The Son is spoken about many times by the prophets.
The prophet Daniel and King David even see the Son in power and glory being worshipped!
And Muslims should be the last people to accuse anyone of paganism, just look at what they pray to 5 times a day. They view of Heaven reflects the pagan Valhalla and Hindu paradise. Only pagans can sit their and dream about food and drink and women in heaven!!...The list just goes on.