The importance of historical accuracy can not be overstated. Historical accuracy is one of the essentials for proper understanding of any given topic. With this we can also include the necessity of being open to the fact that perhaps what you know to be historical fact is actually incorrect, regardless of the source.
What has prompted my reflection concerning the importance of historical accuracy is the problem of St. Photius, Patriarch of Constantinople. This issue, which is disciplinary rather than doctrinal, constitutes one of the major divides between Rome and Constantinople. As far as historical figures go he is one of the most contentious. The reason for this is largely due to a wrong understanding of history. For centuries the prevailing view in the West has been that Photius was a usurper of the patriarchal throne of Constantinople and the father of the schism between East and West. Needless to say, he would not be and has not been looked upon to kindly by Church historians and theologians. Today this view of Photius is perpetuated mainly through the Catholic Encyclopedia (completed 1914) on NewAdvent.org. Understandably (nothing else should be expected) the Catholic Encyclopedia took its information for St. Photius from Western scholarly works of that time. The problem with these works is that the authors never seriously questioned the Western view of Photius. Their work was written from the bias of the already generally accepted view. It would not be until 1948, 34 years after the Catholic Encyclopedia was finished, that this view would be seriously challenged. That challenge came from Francis Dvornik, S.J. in his book The Photian Schism.
At the moment I am 90 pages in and Dvornik has certainly exceeded my expectations. I am extremely impressed with the degree of scholarship and his very thorough examinations and comparisons of source material. If one is going to form an opinion about St. Photius, be it good or ill, they need to read this book.