McCullough considered his Yale undergraduate years studying English and painting among the most formative of his life. In 2006, he was invited to speak for the “Yale Tomorrow” fundraising campaign. His speech focused on three early Yale figures; his research into these men led him to write The Pioneers (2019), an outcome he attributed to his belief in the value of curiosity and his conviction that one thing leads to another.

The speech frames the love of learning through three Connecticut-born, 18th-century polymaths.

Reverend Dr. Ezra Stiles, Yale’s seventh president, kept the small, financially fragile institution alive during the Revolutionary War and began its transformation into a university. A linguist, astronomer, and president of the Connecticut Society for the Abolition of Slavery, he was widely considered the most learned man in America. His 1771 portrait by Samuel King was staged at Stiles’s direction with the subject surrounded by books including Isaac Newton’s Principia (1687), Plato, and an astronomical chart, distilling his scholarly identity. Stiles died in office in 1795.

Colonel John Trumbull, aide to General Washington and a patriot-artist, donated nearly 100 paintings to Yale in exchange for a $1,000 annual annuity. The Trumbull Art Gallery he designed was the first campus museum in the nation.