From Stream.org:

The Second Amendment to the U.S. Constitution didn’t appear out of thin air. In fact, it’s practically plagiarized from the English Bill of Rights. Parliament adopted that in 1689 for one specific reason: to protect the religious freedoms of Puritans and other “low-church” Protestants. They’d been persecuted, legally, by British kings for more than a century. So Parliament included in the bill the proviso that “no Protestant” could be denied the right to carry arms. The link between gun rights and religious freedom was spelled out in the text. (Alas, it left us Catholics out — but that got fixed in the American version, a century later.)