Define Christianity

[Lek]

To be a Christian is it really necessary to believe:

That Jesus was born of a virgin named Mary;

Tortured by Pontius Pilate;

Was crucified (as opposed to so other death);

Is seated at the right hand of god;

That the number of days before he rose from the dead was three no less and no more;

That god will judge the living and the dead;

That there is a holy spirit;

That there is a catholic church;

In communion?

Or is belief in Jesus as lord and savior enough?

This isn't a gotcha question.  I really want to know.  How much of this is necessary to be a Christian?

None of the first christians who came into the church on Pentecost knew all or most of these, but they were still christrians.  I'm not sure that the original apostles understood the doctrine of the Trinity, which became accepted by the orthodox church as a later time.  Peter told the crowd the following:

36 "Let all the house of Israel therefore know for certain that God has made him both Lord and Christ, this Jesus whom you crucified.” 37 Now when they heard this they were cut to the heart, and said to Peter and the rest of the apostles, “Brothers, what shall we do?” 38 And Peter said to them, “Repent and be baptized every one of you in the name of Jesus Christ for the forgiveness of your sins, and you will receive the gift of the Holy Spirit. 39 For the promise is for you and for your children and for all who are far off, everyone whom the Lord our God calls to himself.”  Acts 2

Earlier Peter had told the crowd that Jesus had been put to death and that the Father had raised him from the dead.  This would indicate that one must accept the Jesus of whom Peter had spoken, who had risen from the dead.  Just to believe that Jesus was a good man and a great teacher, but did not rise from the dead, would not qualify one to be called a christian.  That would be like saying "I follow President Obama".  But when asked: "Who is President Obama?", he replies "the King of England".  Obviously he isn't a follower of President Obama.