Roman Emperors <a href="https://en.wikipedia.org/wiki/Diocletian" id="mwEQ" rel="mw:WikiLink" title="Diocletian">Diocletian</a> and <a href="https://en.wikipedia.org/wiki/Maximian" id="mwEg" rel="mw:WikiLink" title="Maximian">Maximian</a> appoint <a href="https://en.wikipedia.org/wiki/Galerius" id="mwEw" rel="mw:WikiLink" title="Galerius">Galerius</a> as <i id="mwFA"><a href="https://en.wikipedia.org/wiki/Caesar_(title)" id="mwFQ" rel="mw:WikiLink" title="Caesar (title)">Caesar</a></i> to Diocletian, beginning the period of four rulers known as the <a href="https://en.wikipedia.org/wiki/Tetrarchy" id="mwFg" rel="mw:WikiLink" title="Tetrarchy">Tetrarchy</a>.