'Son of Man' is practically the only self-designation employed by Jesus himself in the gospels, but is used in such a way that no hint is left of any particular theological significance. Still, during the first many centuries of the church, the expression as it was reused was given content, first literally as signifying Christ's human nature. Later 'Son of Man' was thought to be a christological title in its own right. Today, many scholars are inclined to think that, in an original Aramaic of an historical Jesus, it was little more than a rhetorical circumlocution, referring to the one speaking. Mogens Müller's 'The Expression 'Son of Man' and the Development of Christology: A History of Interpretation' is the first study of the 'Son of Man' trope, which traces the history of interpretation from the Apostolic Fathers to the present, concluding that the various interpretations of this phrase reflect little more than the various doctrinal assumptions held by its interpreters over centuries.