From an interview with Mark Wunderlich who participated in the 2010 Poets Forum in New York City, Oct. 28-30.
Mark Wunderlich: This is based on an 18th-century document that I saw, written in German. It was a house blessing. It's held at the Library Company of Philadelphia. I used the title of what this document was called, and it was a "Heaven Letter."
These were kept in people's homes as charms to protect the home. And it was believed they had mystical properties. I've read this one, and I chose to adapt it. This is called "Heaven Letter."