Giordano Bruno was a Christian; the Catholic Inquisitors who burned him at the stake were not. When I say he was a Christian, I do not mean that he went to mass and followed all the rules of the Church. Nor when I say that the Church fathers were not Christians do I mean that they did not go to mass or disobey any rules. They truly believed that they were Christians and Bruno was a heretic. But in his life, Bruno lived like Christ, while those Inquisitors who killed him did not.
The story of Christ is a man who followed truth wherever it took him, even if that meant being persecuted, hated, tortured, and sentenced to death by crucifixion. He followed Truth, the Word of God, and followed it to his death. By doing so, he would live forever after. You cannot deny the truth of Christ's immortality by the mere fact that you and I know His name today, 2,000 years later.
Those who do the same as Christ and follow the truth will live an eternal life as well. Bruno did just that; he followed the truth of the heliocentric model of the universe, and like Christ, it resulted in persecution and hatred from his contemporaries and the institutions of authority. During Jesus's life, that was Rome; during Bruno’s life it was the Catholic Church itself. Those powerful institutions in control of society killed them for the truth they tried to spread because of the threat that truth posed to their authority.
Bruno was burned at the stake for his heresy, but by following the truth he now enjoys eternal life—because the truth cannot die. The truth never dies. Those who follow it will not die either. Bruno's ideas about the universe are still alive, more so than ever, because they are true. And Christ's story is still alive because it is true. Bruno's life, death, and legacy are proof of the truth of Christianity. Never mind that the Church killed Bruno—they were not acting like Christ when they did so.
Being Christian is not about going to church, or saying a certain number of rosaries, or going to confession, or any other number of rituals. To be Christian is to live like Christ, which is following the word of God, which is following the truth—wherever it leads. That may lead to suffering in this life, but ultimately in the next life the Truth will set you free.