Floruit

Floruit (often abbreviated fl. or flor. and sometimes to show it is ) refers to a period of time during which a person, school, movement or even species was active or flourishing. It is the third person, singular, perfect tense form of the Latin verb florere — 'to flourish'. It is widely used in and historical writing, when the birth or death dates are unknown, but we do have some other evidence indicating when a person was alive. For example, if there are wills attested by John Jones in 1204, 1207 and 1229, and a record of his marriage in 1197, it should be written as "John Jones (fl. 1197–1229)".