black borders on letters and envelopes
... that people in the Victorian era commonly placed black borders on letters and envelopes to signify that they were in mourning?
... that people in the Victorian era commonly placed <b id="mwAdE"><a href="./Mourning_stationery" id="mwAdI" rel="mw:WikiLink" title="Mourning stationery">black borders on letters and envelopes</a></b> to signify that they were in mourning?