I am an entrepreneurial religious leader on the path to god hood, and have been said to be able to heal individuals of illnesses incurable by science. It has even been claimed that I brought a dying man back from the brink of death, restoring him to full health in a matter of hours. Due to these acts, I have managed to assemble a significant following. I have discovered that the secret to becoming a deity is the belief of the amount of your worshipers, if one is able to harness the energy of that worship onto themselves. I have decided to use this phenomenon to begin a worldwide religion that will eventually result in my ascension to godhood.
The problem is that I am competing against other mainstream religions who have a large claim to earth's population, the three biggest being judaism, christianity, and islam. These monotheistic faiths worship the same god with similar principles. They have the same roots, with judaism being 1.0, christianity being 2.0, and Islam, being the latest, 3.0. They have the benefit of being around for many centuries and have a large headstart.
Religious leaders today who fancy themselves divinely inspired, such as a new prophet or second coming of christ, are largely seen as cult leaders to most of the world. At best, delusional egomaniacs with delusions of grandeur, or at worst, opportunistic con men who swindle people out of money and common sense. Jim Jones, David Kuresh, etc, all gathered a significant following but ended badly and today are remembered as lunatics. Even the most successful "new" religion, scientology, is regarded by most as nonsense founded on the insane rantings of another con man.
Trying to start a faith today, in a world where technology is so advanced and most people are at best, saturday morning believer, and at worst, skeptics, is very difficult. In order to compete with larger faiths, I need to insert myself into a specific point in the timestream, where I can begin spreading my faith to ensure that it grows wide enough to compete with the others and become accepted as legitimate in the modern world. I can bring nothing back with me, save for myself. However, I cannot simply go back to before the others were started. The farther I go back, the less control I have about where and when I land in the timestream. I need to pinpoint a time period closest to the modern world as possible, but far enough that it has time to develop and spread world wide.