Complex sentence: Though Gibbs was unable to graduate from the seminary, he was ordained in 1856, and became pastor of Liberty Street Presbyterian Church in Troy, New York, where Henry Highland Garnet had been pastor.
Split into simpler sentences: Though Gibbs was unable to graduate from the seminary, he was ordained in 1856. He was called as a pastor of Liberty Street Presbyterian Church in Troy, New York, where Henry Highland Garnet had been pastor.