The Leeds Playbill project is a fabulous web archive of some of the oldest circus posters and vintage playbills around. Most of the stuff is dated around 1860-1890, and a lot of it is torn or decayed or burned, in case you didn't trust the date. It's a great source of inspiration for old-school typography and antique press printing.
Leeds Playbill Gallery
Woodtyper blog post on Leeds Playbills