\documentclass[a4paper,landscape]{foils}
\usepackage[utf8]{inputenc}
\usepackage{amssymb}
\usepackage[svgnames]{xcolor}
\usepackage{graphicx}
\usepackage{isabelle,isabellesym}
\usepackage{isabellefoils}
\usepackage{pdfsetup}
\parindent 0pt\parskip 0.5ex
\urlstyle{sf}
\isabellestyle{it}
\MyLogo{}
\isadroptag{theory}
\isafoldtag{proof}
\begin{document}
\title{\titlestyle Simple slides with FoilTeX}
\author{Makarius Wenzel, Augsburg \\ \url{https://sketis.net}}
\date{}
\maketitle
\vfill
\begin{center}
\includegraphics[width=0.15\textwidth]{isabelle_logo}
\end{center}
\vfill
\input{session}
\end{document}