What does "ff." mean in a history textbook, referring to a date?

My history textbook has a timeline and it says on it

1730 ff. - Massive population riseWhat does "ff." mean in a history textbook, referring to a date?
It means "following." For example, on a timeline of US History, Industrialization (1830 ff.) would mean that the process of industrialization in the U.S. started in 1830 but continued on well after that.



Actually is short for 'folios following'.