one parent who was already a citizen of the state. (5) In the earliest known case to articulate jus soli in England, Calvin v. Smith (Calvin’s Case), it was agreed that the statuses of subject and alien were determined by whether a person was born owing allegiance to the sovereign, as indicated by the Latin phrase ad fidem regis. (6) Sir Edward Coke, one of the judges deciding Calvin’s Case, extrapolated one exception to jus soli, writing, But if enemies should come into any of the King’s dominions, and surprise any castle or fort, and possess the same by hostility, and have issue there, that issue is no subject to the King, though he be born within his dominions, for that he was not born under the King’s ligeance or obedience. But the time of his birth us of the essence of a subject born