Americus Callahan
...that the first windowed envelope was designed in 1901 by Americus Callahan?
...that the first windowed <a href="./Envelope" id="mwDPQ" rel="mw:WikiLink" title="Envelope">envelope</a> <i id="mwDPU">(pictured)</i> was designed in 1901 by <b id="mwDPY"><a class="mw-redirect" href="./Americus_Callahan" id="mwDPc" rel="mw:WikiLink" title="Americus Callahan">Americus Callahan</a></b>?