Because the sources of history books that were not in our possession before have become available to us today, thanks to the ease of access to sources and information; The manuscripts and documents - which the researchers were traveling to obtain and spend weeks and months in the libraries - have become with the hand, and it became obligatory for the historian to discuss what he wrote from his predecessors, trying to develop the historical writing process to reach angles that have not been considered before. History is not written once, because historical scientific methodologies and theories are renewed and constantly evolving, and the Gulf researchers who are published in the Arabic language - in particular - must keep pace with this scientific development and its meeting. History is not written once because the political conditions in which some historians wrote their books have changed, and the prohibitions in their time changed, this research freedom makes history write more than once.