Historiography of early Christianity is like telling the story of how Christianity started a long time ago. It's like how your parents or grandparents tell you stories about what happened when they were young.
The story of early Christianity goes back to a time when people believed in many gods and not just one God. But then a man named Jesus came along and taught people about the love of God and how to be kind to others. He also performed many miracles, like healing the sick and feeding a crowd of people with just a few loaves of bread and fish.
After Jesus died, his followers started telling others about his teachings and miracles. They wrote down their stories in books called the Gospels, which are part of the Bible. But not everyone agreed on what exactly happened or what was the right way to interpret Jesus' teachings. So different groups of Christians started telling their own versions of the story, and sometimes even disagreed with each other.
As time went on, more and more people joined the Christian community, and the Church became more established with its own leaders and doctrine. People started writing books about the history of Christianity and how it came to be, but not all of these books agreed with each other either. Historians continue to study and debate the history of early Christianity, trying to understand what really happened and how people's beliefs and interpretations changed over time.