Structuring theories is one of the main approaches to reduce the
combinatorial explosion associated with reasoning and exploring large theories.
In the past we developed the notion of development graphs as a means to
represent and maintain structured theories. In this paper we present a
methodology and a resulting implementation to reveal the hidden structure of
flat theories by transforming them into detailed development graphs. We review
our approach using plain TSTP-representations of MIZAR articles obtaining more
structured and also more concise theories