Eventually, during the reign of Diocletian, and edict was passed that anyone who would not sacrifice to the emperor as a god was to be put to death. Whether the tens of thousands of people the Roman pagans tortured, burned, and otherwise executed were all Christians is unimportant; they refused the offical cult of the Emperor. Many of these are still recognized as Martyrs for the Christian cause.
In 64 Christian era, there was a great fire in Rome that caused destruction of the city. Many citizens accused the emperor for starting it, and to save himself, he pushed the blame on the unpopular christians, although through investigation suggested they were not guilty in starting the fatal fire. The reason why the Christians were hated was because they worshipped their God, and refused to bow down to the emperor and worship him. Christians were often confused with Jews, who had a repution of being stubborn, for they only worshipped their own God and no one else. Therefore, they were often accused of disoloyalty since they refused to respond to orders that were contrary to their beliefs. The laws of the time were strong, and whoever did not bow down when commanded to had to face severe punishments, often death. These people who died becuase of their beliefs, are what we call martyrs. They were tortured harshly, usually made enjoyable to the audience. It was as if they were played with. Some were burned on the stake, others were torn apart by animals, and It was like a circus game, and people started to pity them because it did not benefit the public, but ashamed themselves.