This chapter addresses the developments in the practicalities and documentation of the process of canonization from the high Middle Ages to the late medieval period. It starts with the discussion of the process of validating sainthood before the official process was introduced and in particular the importance the official Vita and the local bishops had in this process. Following this, Paciocco analyses the developments of the 12th and 13th centuries, which saw increasing influence of the Canon Law for the validation of sainthood and finally the development of the Roman-canonical procedure. After this, the chapter moves on to discuss the actual practicalities of cult promotion and recording of the process, also in its curial phase. The final part of the chapter discusses the later developments of the Avignon period and the 15th century. The analysis of the chapter demonstrates the uniform principles but varying practices behind the processes and the source material that derives from them.