In the mid-nineteenth century, my God, the facial hair on men!
Men took their lead from celebrities in the mid-1800s, just as they do today.
Many credit Abraham Lincoln with the horseshoe beard.
But it seems the fashion trend began in 1852, with the Hungarian Revolutionary Louis Kossuth, who shaved his chin. (Kossuth was a clothes horse in general, and style-crazed Americans also went mad for his tall hat with feathers, and his unique style of trousers. See this entry at Highbeam Research for more info.) Lincoln's daring move, then, was to also shave the mustache.
In my high school days, some still sported the Lincoln horseshoe ...
According to Merriam-Webster, "side-whiskers" was first coined around 1858. In the Civil War, a certain Ambrose Everett Burnside became a hair legend as side-whiskers started being called "sideburns." Click here for the full story, with art.
Today, the slang sideburns has been eclipsed by "mutton chops," for their obvious shape. To learn about this fashion, and all about beards, there's a website called ... wait for it ... All About Beards.