Pegg
Jehovah our God is One
The Crusades were done by the Catholics, and we Orthodox were also savaged by the Crusaders--for example, in 1204 when the Catholic Venetians sacked Constantinople. Our altars were desecrated as Crusaders had sex with prostitutes atop them, the chalices from whence we served the Eucharist were used by Venetian drunkards as vessels for wine and beer, our nuns and women were raped, our clergy, monks and men were slaughtered, our relics and icons were stolen or destroyed.
Orthodox soldiers fought for the Empire as long as it was giving Caesar Caesar's due, and not overstepping the bounds set by Christ.
this is very sad. Christians killing christians...both of which were serving the interests of the Roman empire.
And completely ignored Christs commands:
John 13:34  I am giving you a new commandment, that you love one another; just as I have loved you, you also love one another. 35 By this all will know that you are my disciplesif you have love among yourselves.
Do you realise that by going to war for the empire, they were no longer Christ's disciples? And today the continue to fight christians in other lands and go to war for their 'empires'
You have no proof that Christianity adopted any pagan beliefs whatsoever.
Encyclopædia Britannica
Nothing perhaps has tended more thoroughly to corrupt Christianity than the introduction into it of superstitions which are really pagan themselves, or have been suggested by pagan practices. Paganism, unable to oppose Christianity successfully, has done much to corrupt it, and in numberless ways has made inroads into its purity.
MClintock and Strongs Cyclopaedia
The simplicity of the Gospel was corrupted; pompous rites and ceremonies were introduced; worldly honors and emoluments were conferred on the teachers of Christianity, and the kingdom of Christ in a great measure converted into a kingdom of this world.
Essays and Sketches, the 19th-century Roman Catholic cardinal John Henry Newman
The phenomenon, admitted on all hands, is this:That great portion of what is generally received as Christian truth is, in its rudiments or in its separate parts, to be found in heathen philosophies and religions. For instance, the doctrine of a Trinity is found both in the East and in the West; so is the ceremony of washing; so is the rite of sacrifice. The doctrine of the Divine Word is Platonic; the doctrine of the Incarnation is Indian.
The Development of Christian Doctrine, Cardinal Newman
Constantine, in order to recommend the new [Roman Catholic] religion to the heathen, transferred into it the outward ornaments to which they had been accustomed in their own. Then, after listing many of the practices of his church, the cardinal admits that these are all of pagan origin, and sanctified by their adoption into the Church.
There is plenty of evidence that the church adopted all their practices (which they are currently and still practising) from pagan religions. Its even recognized by people within the church itself.