1828-1832 Charles Carroll of Carrollton, Last Living Declaration of Independence Signer, free frank signed cover to Signers Collector William Buell Sprague

Interesting Association: Free Frank Panel (circa 1828-1832) signed by the last surviving Signer of the Declaration of Independence, Charles Carroll of Carrollton. In 1828, the only surviving signer of the Declaration of Independence was Charles Carroll of Carrollton. He became the last living signatory after the deaths of Thomas Jefferson and John Adams on July 4, 1826.  

Addressed to Declaration Signers Collector "The Reverend Mr. William B. Sprague" (William Buell Sprague). Likely free franked sometime between May, 1828 and 1832 since Charles Carroll was granted the honorary franking power from May 24, 1828 and passed November 14, 1832. Reverend Sprague was the first to collect the autographs of all 56 signers of the Declaration of Independence. 

Additional reading about Sprague: https://www.logcollegepress.com/blog/2021/7/17/william-b-sprague-an-american-collector