What caused the Old Side and New Side schism among American Presbyterians?

The schism between the Old Side and New Side Presbyterians, which lasted from 1741 to 1758, was caused by the religious revivals of the 18th century known as the Great Awakening.1

The division emerged from fundamental disagreements regarding the nature of the church and religious practice:

• New Side: Composed largely of New England Puritan Presbyterians, this group was pro-revival. They emphasized the Christian life as the basis of the church and favored the emotional, evangelical methods of the Great Awakening, which prioritized personal conversion experiences.1
• Old Side: Composed primarily of Scotch-Irish Presbyterians, this group was anti-revival. They viewed doctrine as the primary basis of the church and insisted on strict adherence to the Westminster Confession. They were critical of the revivalists for what they perceived as emotional excesses and for the practice of preaching in settled parishes without proper authorization.12

The two groups eventually reunited in 1758, leading to a period of significant growth for the church.1