According to <a href="https://en.wikipedia.org/wiki/Edward_Gibbon" id="mwMw" rel="mw:WikiLink" title="Edward Gibbon">Edward Gibbon</a>, <a href="https://en.wikipedia.org/wiki/Osman_I" id="mwNA" rel="mw:WikiLink" title="Osman I">Osman I</a> invades the territory of <a href="https://en.wikipedia.org/wiki/Nicomedia" id="mwNQ" rel="mw:WikiLink" title="Nicomedia">Nicomedia</a> for the first time, usually considered to be the founding day of the <a class="mw-redirect" href="https://en.wikipedia.org/wiki/Ottoman_state" id="mwNg" rel="mw:WikiLink" title="Ottoman state">Ottoman state</a>.