With that, when Ben Franklin promoted "rational Christianity" in his 1772 letter to the Arian Richard Price, it was done in the context of promoting unitarianism. As Franklin wrote:
If he had come to town, and preach'd here sometimes, I fancy Sir John P. would now and then have been one of his hearers; for he likes his theology as well as his philosophy. Sir John has ask'd me if I knew where he could go to hear a preacher of rational Christianity. I told him I knew several of them, but did not know where their churches were in town; out of town, I mention' d yours at Newington, and offer 'd to go with him. He agreed to it, but said we should first let you know our intention.