At the time of the codification of first Hungarian Code of Criminal Procedure, the legal literature regarded the limited scope of second-instance revision as a limitation of appeal in favour of the defendant, and placed it in this sense inside the procedural doctrinal system. This idea, which is quite alien to contemporary procedural thinking, which focuses on speeding up and facilitating proceedings, raises the question: what are the principles on which the limited scope of review is considered as a guarantee for the defendant? In order to answer this question, my aim in the present study is to explore the system of principles that shaped the turn-of-the-century jurisprudence concerning the legal power of the second instance to grant review.