Claims that the Catholic Church of today is the original church

[Universalist Catholic]

Okay, so I did some research about how Constantine influenced the Catholic Church, but all I found were some Catholic sites trying to claim that these accusations are just anti-catholic attempts to put down the Church. 
http://www.ancient-future.net/constantine.html
Claims that Mary was always honored the same way as now?  Last I checked, she was simply highly honored, but some people today in the Church have made several Goddesses out of her.  Not all Catholics, but some of them have all these devotions, Fatima, Lourdes, Guadalupe, Ect.  Today, it seems more like people have made a cult out of her. 
Claims that the Eucharist was understood exactly as it is today?  Last I checked, it was previously understood to be a mystery, and a holy meal to recall the passion and death of the lord.  I dont think it was until much later that the new regulations were made, such as one with mortal sin could not participate in the meal, or that a qualified priest could only perform the meal. 
But I would definitely have trouble accepting the fact that Jesus would be the hardest on the organized Church only to start another organized Church of the same fashion as the previous one. 

[Jerm]

It's actually a very good thing that this is all you found regarding Constantine's influence because most of the current "information" put out by modern Evangelicals concerning his influence is grossly overstated and is based more on the Da Vinci Code than history.  Anywho, you are right in that alot of Catholic doctrine has been developed over time.  However it is, as you point out, based in history.  I think that in most cases Mary's importance is taken too far but she, along with the other saints, were venerated and honored from the get go.  And regarding the Eucharist, I currently do not subscribe to transubstantiation yet on the other hand the Early Church viewed it as much, much more than merely symbolic (i.e. God is, to use your terms, mysteriously present in the meal though a hard and fast doctrine wasn't developed until later.)  I guess my point is simply that though I disagree on much of the semantics concerning Catholic doctrine, I do believe their assertion that their lineage goes back to the beginning is legitimate.