I have to differ; your reference to its first apparent usage in English literature is no doubt correct; but the actual use of it has been employed ever since in common language.
Strunk and White
Still my Bible
They. A common inaccuracy is the use of the plural pronoun when the antecedent is a distributive expression such as each, each one, everybody, every one, many a man, which, though implying more than one person, requires the pronoun to be in the singular. Similar to this, but with even less justification, is the use of the plural pronoun with the antecedent anybody, any one, somebody, some one, the intention being either to avoid the awkward “he or she,” or to avoid committing oneself to either. Some bashful speakers even say, “A friend of mine told me that they, etc.”
Use he with all the above words, unless the antecedent is or must be feminine.