Hoca Sadeddin Efendi 16. yüzyılın en önemli tarihçilerinden biridir. Telif ettiği Tâcu’t-Tevârîh adlı eserinde, Osmanlı Devleti’nin kuruluşundan başlayarak Yavuz Sultan Selim’in vefatına (1520) kadar gerçekleşmiş olayları ele almıştır.

Hodja Sadaddin Effendi is one of the most important historians of the 16th century. In his work entitled as “Tâj al-Tawârîh”, he dealt with the events from the establishment of Ottoman history (1299) to the death of Selim the Resolute (1520). Tâj al-Tawârîh has been a reliable and widely read book as a source that explained the Ottoman history from the beginning to the 16th century. Therefore, the book is one of the brightest examples of the 16th century. It has an important place among Turkish and world historians in terms of historical science. For this reason, some supplements have been written on the work. In Europe, the book was in great demand and from the 17th century, it was fully translated into French, German and Italian, and partially into Russian, English and Hungarian. The information that he gave in his book shed light on Ottoman History and was also used as a source of Ottoman histories that were compiled later on. In compiling his work, he promoted the events that were narrated using religious sources such as verses, hadiths and proverbs according to the importance of the subject. This situation shows that he was very knowledgeable about religious and historical information.He states that had a heavy cross to bear with the writing of events in the periods of Selim the Resolute and Suleiman the Magnificent, and has also written the book with all the details in "uslûb-i itidâl" with bounds on praise and criticism. However, he states that the readers should be careful about the topics of the first period that he has written in his book because of that it has been a long time and the people who reported the events might have confused the information, and that he might not be able to provide reliable information.He stated that there may be some deviations as long years passed in the reporting of the first period events because of that the narrators might have confused some narrations and even added their own opinions. He also states that the recent events in his book are true and there is no fabricated news in his statements.In his book, he went on to describe some events in summary by only mentioning the names. The reason for this is either that he could not find any information or sources about the events, or he could just find that information in the sources that he had reached.In explaining the events, he narrates some of the events under the headings of "Latîfa and Hikayât" in order to not boring for the reader. By this method, he has retained the work from being a work full of battle scenes. He tried to provide a better understanding of the events, leave deep traces in the minds of the readers and encourage people for goodness by means of the subjects explained under the headings of "Latîfa and Hikayât". He, like modern historians, tried to seek and investigate the underlying reasons of social, economic, political and religious events. He stated the reasons for the events and made criticisms where necessary. He compared the events and sources. In this way, he transformed the knowledge of history into a philosophical system.He also gives information about social events of the period such as famine, earthquake, fire, lunar and solar eclipse, ceremonies, epidemic diseases and deaths. The information given by Ottoman history writers about the first establishment of the state and the following years is generally based on the oral folk epics. These are valuable information about the culture, social life and belief of a nation at that time.In the preface of book, he gives some information about the definition of history, its subject and aims, the features that a historian should have, and the methods that a historian should follow. According to him, the history is to convey to future generations by writing on the services of those who serve on the path of nation and religion, their good habits, life stories and struggles.In his book, which is one of the most important sources in the history of the Ottoman Empire, he narrates the events that occurred from the establishment of the Ottoman Empire to the end of the Selim the Resolute period. Tâj al-Tawârîh consists of nine chapters that each chapter describes the events that occurred during the period of a Sultan.