[coliveira]

First of all: the accounts are not first hand. They were in fact anonymous. Nobody put their names in these Gospel-style compositions, identifying themselves, until very late when the church decided to name them as we now have.

Second of all: these accounts are not independent. There is the gospel of Mark, and them other authors went on copying most of the previous books, but adding sections that frequently contradict others. So, what we have are not 4 to 6 different accounts, we have a single story that has been copied and edited by several anonymous people.