Whereof is used in classic literature, giving a formal or old-fashioned tone. He recited verses, the themes whereof were inspired by ancient folk tales.
Pro Tip 2/3
Implicit Knowledge
Implies the speaker knows more about the topic, adding a layer of understanding. She mentioned the experiment, whereof results were yet to be disclosed.
Pro Tip 3/3
Restricted Usage
Modern English seldom uses 'whereof'; be mindful of its archaic nature. The old text spoke of traditions, whereof many are no longer observed.