The second influence which moved Mr. Campbell toward a nonsectarian view of religion was the writings of the philosopher, John Locke, especially his _Letters Concerning Toleration_. In these essays Locke had urged toleration, not only by the state toward dissenting groups, but also by the church toward varieties of theological opinion within itself. Sentences could be quoted from Locke which sound as though they came straight from the _Declaration and Address_. All this rested on a philosophy carefully worked out in his _Essay on the Human Understanding_. Thomas Campbell diligently studied these two books by John Locke and made them required reading for his son Alexander, who never ceased to give them his unbounded admiration. Seceding from the Seceders Partly because of ill health in his forties (he lived to the age of ninety-one), and partly to find a place of ampler opportunity for his seven children, Thomas Campbell migrated to America in 1807, as many of his Ulster neighbors had done before him. He landed at Philadelphia on May 13, fortunately found the Associate Synod of North America, which represented all the Seceders in America, in session in that city, presented his credentials and was received into the synod on May 16, and two days later was appointed to the Presbytery of Chartiers in southwestern Pennsylvania. The minutes of the presbytery show that he had preaching appointments at “Buffaloe” (now Bethany, W. Va.), Pittsburgh, and other points beginning July 1. So, in less than three months after preaching his farewell sermon in the Ahorey church in Ireland, Thomas Campbell was ministering to a circuit of communities on the American frontier.