The minstrels of the 1830s onward picked with two fingers, thunb and index. Later this was called stroke style and it evolved into modern clawhammer. Stroke style can be very intricate at times, switching leads from index to thumb, and back to index again. The old 19^th century minstrels could even play jigs or other tunes in 6/8 time, a feat most modern clawhammer players shun like the flu. There are a couple of reprinted banjo instruction books out. One is Tom Briggs' Banjo Instuctor written in the 1850s by Tom Briggs, the other is Banjo with or without a Master and I forget the author's name. The second book was first published about 1866, I believe. If you get either of these books, be prepared to read music. They weren't written in tablature.
Jim