Complex sentence: Joseph Sr., was also one of the Eight Witnesses of the Book of Mormon's which was translated by Joseph Jr. from the Golden Plates, and was the first Presiding Patriarch of the Church of Jesus Christ of Latter-Day Saints.
Split into simpler sentences: Joseph Sr., was also one of the Eight Witnesses of the Book of Mormon's which was translated by Joseph Jr. from the Golden Plates. In addition, Joseph Sr. was the first Presiding Patriarch of the Church of Jesus Christ of Latter-Day Saints.