Source: Galadrielle Allman: 'Please Be With Me: A Song For My Father, Duane Allman', pages 269-270 and 369-370 (Spiegel & Grau, 2014)

September 5, 1970
Ramada Inn
Milwaukee, Wisconsin

Sunday

Dearest Spoon,
Thanks for the sweet secret message. Please try and have a little faith, honey, and everything will be alright.
Eric Clapton has asked me to join his band. I really don’t know what to do, but don’t mention a word of this to anyone at the house, or leave this letter where others might read it and do something foolish. It would mean about $5000 a week to us, as well as a home in England and a lot of things we’d like to have. We’ve cut a really super album together, and Eric plans a European as well as an American tour, and the receipts would be phenomenal on both. I’ll be getting 20% of all of it, so I plan to do both of those tours with him.
I’ll write more later when my thought is more stable. I’m really up in the air right now.
All my love to Gragri and everyone there.

Love Always,
Duane

P.S. Shhh!
 

(The letter is dated September 5, 1970, but Duane wrote it on Sunday, and that was September 6, 1970)