Yes indeed he did! It was the pen name/fictional character he used as a young apprentice boy in order to get letters published in his brother James's newspaper---Franklin figured his brother wouldn't let him publish under his own name, so he submitted his pieces under the name Silence Dogood. The letters proved pretty popular and James was impressed with them, but when Ben let slip that they were his work, it created a rift between the brothers because James felt that Ben was getting a big head due to the praise his letters had gotten. Here are the letters!