Some things are not invented, they just happen. Think of Isaac Newton who, if he hadn`t found himself standing next to an apple tree one day, might never have discovered gravity. And so it was with Port wine.
Under the reign of Louis XIV, during one of their many disputes with the English, the French restricted the import of English goods into France, provoking the English king, Charles II, to retaliate by forbidding the import of French wines into England.