Complex sentence: By 1790, they had founded the First African Church of Lexington, now known as the First African Baptist Church, the first black congregation west of the Allegheny Mountains, the oldest black Baptist congregation in Kentucky and the third oldest in the United States.
Split into simpler sentences: By 1790, they had founded the First African Church of Lexington, now known as the First African Baptist Church. It was the first black congregation west of the Allegheny Mountains, the oldest black Baptist congregation in Kentucky and the third oldest in the United States.