With the accession of Hadrian in 117 CE, after more than a hundred years of imperial portraits with no trace of facial hair (only a little stubble, if they were supposed to be in mourning), emperors started to be portrayed with full beards, a trend that lasted throughout the rest of the century and well after the period covered by this book. It is a guaranteed way of dating all those imperial heads that now line museum shelves: if they are bearded, they are after 117 CE.
