ancient lovers

this is something i read about in my history book last week...
in ancient egypt, two lovers would call each other "brother" and "sister". there was a little bit of a poem by a dude who was lovesick for his "sister". as Christians, our lovers (i know, it's an old-fashioned, soppy word ;P) should be our brother or sister in Christ. i kinda don't have anything else to add to that, but i thought it was really interesting...