J. Gresham Machen
One of the principle founders of our denomination was J. Gresham Machen (1881-1937). He was a theologian, author, Bible scholar, and preacher who taught for many years at Princeton Theological Seminary, and later founded Westminster Theological Seminary in Philadelphia, Pennsylvania. 

Through his steadfast defense of the faith, it was clear that God had raised up this man to fight the good fight. Perhaps his most important book was Christianity and Liberalism. This book served as a wake-up call to the dangers of liberalism. Many conservative pastors in the PCUSA silently assumed that at worst, liberalism was merely a perversion of true Christianity. But as Machen’s masterpiece made clear, liberalism was far worse: it was a completely different religion altogether, it was spreading through the denomination like wildfire, and it needed to be opposed at all costs.

When Machen learned that the denomination’s official missions agency was funding liberal missionaries (including well-known author Pearl S. Buck), he fought back by pressing charges against them. However, the liberals prevailed in the church courts. This meant that the denomination would continue to send missionaries overseas who denied essential truths—including Christ being the only path to salvation.

Machen and his allies then responded by forming the Independent Missions Board, which would fund only missionaries who were faithful to the historic Christian faith. Sadly, his opponents passed a resolution that ministers and churches within the denomination could only fund and work for the mainline church’s officially sanctioned mission board; those who did not adhere to this resolution would be subjected to church discipline. As president of the Independent Missions Board, Machen refused. He was then prosecuted, and eventually declared guilty of “disturbing the peace” of the Church. 

In sum, Dr. Machen was found guilty of two things: funding missionaries who were faithful to their Lord Jesus Christ, and refusing to submit to an order that would have violated his conscience and his liberty as a Christian.

Forming a New Denomination, Machen’s Passing
It was now clear that Machen could no longer remain in the mainline denomination. So on June 11, 1936, he and a small group of like-minded ministers formed the Presbyterian Church of America. At last, there was a truly Reformed Presbyterian denomination.

Sadly, Machen would not live long to see the fruits of his labor. In late December of that year, while traveling through North Dakota to promote the new denomination, he caught a severe case of pneumonia. One of his last acts was to send a telegram to his colleague, John Murray, in which he wrote these words: “Thank God for the active obedience of Christ. No hope without it…Isn’t the Reformed faith grand?”

On January 1, 1937, J. Gresham Machen entered into glory.
A young theologian and protégé of Machen, Dr. Cornelius Van Til was devastated. One might even argue that a young denomination losing a man of Dr. Machen’s caliber would have been analogous to the United States of America losing General George Washington six months into the Revolutionary War! 

As OPC historian John Muether records, Van Til spoke of his devastation to his father. The elder Van Til looked at his son and quoted from Hebrews, 

"Without faith it is impossible to please God," then walked away.

Dr. Van Til recalled being "sufficiently rebuked" by this response, and it served as a very important reminder: this young denomination did not belong to J. Gresham Machen, or to any other man. Rather, it is Christ’s Church. And as swift as Machen’s departure was, God soon raised up other men to be pastors who would lead the denomination, and he continues to do so to this day.

The "Orthodox Presbyterian Church"
Shortly after the Presbyterian Church of America was established, the mainline Presbyterian Church of the United States of America filed suit. The grounds for this suit was that the name of the new denomination was too similar to their own. 

How would the fledgling denomination respond? Certainly many were tempted to fight back. However, this was a young denomination whose members had already paid dearly for leaving the mainline church: ministers had to forfeit their retirement pensions, and those churches which left the PCUSA lost their property (which was owned by the denomination). Finally, these events occurred during the Great Depression, so financial resources were scarce. So given their limited choices, leaders of the new denomination opted to change its name. In 1939, by one vote, it came to be known as the Orthodox Presbyterian Church (OPC). 

The term “orthodox” might at first seem confusing. To clarify, the OPC is not affiliated with Eastern, Russian, or Greek Orthodox Churches. Rather, “orthodox” means straight thinking. That is to say, we as a denomination are committed to the Word of God as our sole rule for faith and practice. The teachings of Scripture are best summarized in the Westminster Confession of Faith and Larger and Short Catechisms.