Template:Birth based on age as of date/doc

Usage
This template calculates the birth year and current age based on the age as of a date. This is useful when a reference states only their age at the time of the reference's publication.

Syntax
(age age)

The age, year, and day must be supplied as natural numbers; month can be specified as a natural number as well as by name or abbreviation (e.g. "August" or "Aug"). The Gregorian calendar is assumed, with no special support provided for dual dating or the difference between Old Style and New Style dates.

Examples
For example, if a reference dated July 4, mentions that someone is 50 years old, that person's birth year and age can be rendered using (age 50)