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Wingb1if my understanding is correct, christianity i.e protestants = christians (but not catholics) broke off from Catholicism, believing that people can reach God directly without having to go through the priests, and that everyone should have the right to own and read a bible rather than through the priest. Though Catholics and christians essentially worship the same God, there're some differences in their practices and... beliefs, such praying to saints and the rosary. These all, in turn, came from Judaism, for Isralites do not believe that Jesus is the prophecised Messiah.
Well, not exactly. As I wrote in my prior post, There are, basically, three branches of Chistianity: Catholics, Protestantism and the orthodoxs. You have mentioned protestants, so I will try to explain the main characteristic protestant principles, that make them different from catholism:

- Sola Scriptura ("Bible Alone"). They only believe in the teachings that are written in the Bible. We, catholics, believe that our sources and rule of faith are the Bible together with the Tradition (decrees of popes and councils). We also believe in the tradition as the only legitimate and infallible interpreter of the Bible.

- Sola Fide ("Faith Alone"). They declare that the sinner is justified before God (i.e. is acquitted of guilt, and declared righteous) solely on the ground of the all-sufficient merits of Christ as apprehended by a living faith, in opposition to the theory which makes faith and good works co-ordinate sources of justification, laying the chief stress upon works. Protestantism does not depreciate good works; but from our point of view it denies their value as sources or conditions of justification, and insists on them as the necessary fruits of faith, and evidence of justification. In spite of this, In 1999 the Lutheran World Federation and the Catholic Church signed a joint declaration on this matter that made their positions closer than in the past.

- Priesthood of All Believers: This implies the right of laity to take part in the government and all the public affairs of the Church. It is opposed to the hierarchical system, which puts the essence and authority of the Church in an exclusive priesthood, and makes ordained priests the necessary mediators between God and the people. However, not every protestants think exactly the same at this point. We, catholics, believe in the role of laity within the church´s organization, but always by respecting the hierarchy, that is lead by the pope and the rest of the bishops around the world.

Regarding some of the aspects you mentioned, as the praying to saints, It is not compulsory for us to always pray to God throught the saints. In my case, I pray almost the 90% of times, directly to God, without intermediary.

I hope this is useful to you!