# Classicthesis chapter title formatting

How can I modify ClassicThesis to format chapter headings with the word "Chapter" followed by the roman numeral chapter number, a verticle space, and the chapter title? As many know, the default looks like:

While the desired (nay, required) would look like:

I have written the whole thing using lyx, and have been able to change many things to match required formatting.

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Welcome to TeX.SX! Please help us to help you and add a minimal working example (MWE) that illustrates your problem. It will be much easier for us to reproduce your situation and find out what the issue is when we see compilable code, starting with \documentclass{...} and ending with \end{document}. –  Christian Hupfer Jun 24 at 7:54
Christian, Is there a proper way to post a MWE when using LyX instead of LaTeX proper? –  franklin mazzarratti Jun 24 at 22:56

You can add the following code to your preamble, just before \begin{document}:

\newcommand{\RNum}[1]{\uppercase\expandafter{\romannumeral #1\relax}}
\def\ifNumPutRoman#1{%
\if!\ifnum9<1#1!\else_\fi
\RNum{#1}\else#1\fi}

\titleformat{name=\chapter}[display]%
{\relax}
{\centering{CHAPTER \ifNumPutRoman{\thechapter}} \\ }%
{10pt}%
{\centering\spacedallcaps}[\normalsize\vspace*{2\baselineskip}]%


Which gives you this:

\RNum converts thechapter to roman numerics, however, it first needs to be checked if it is a number or not. This could happen when \chapter{} is called in appendix part. The next command, \ifNumPutRoman takes care of this. Credit for this check goes to this answer.

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Pouya, thanks for your answer. This code works as advertised when added to the preamble in a LyX classicthesis document. –  franklin mazzarratti Jun 24 at 23:00