Frederick T. Gates was the chief philanthropic advisor to oil tycoon John D. Rockefeller, arguably the richest person in modern history and one of the era’s greatest philanthropists. Here’s a brief profile from Rockefeller biography Titan (h/t @danicgross):

Like Rockefeller himself, Gates yoked together two separate selves—one shrewd and worldly, the other noble and high-flown…

After graduating from the seminary in 1880, Gates was assigned his first pastorate in Minnesota. When his young bride, Lucia Fowler Perkins, dropped dead from a massive internal hemorrhage after sixteen months of marriage, the novice pastor not only suffered an erosion of faith but began to question the competence of American doctors — a skepticism that later had far-reaching ramifications for Rockefeller’s philanthropies…

Eventually Gates became Rockefeller’s philanthropic advisor, and:

What Gates gave to his boss was no less vital. Rockefeller desperately needed intelligent assistance in donating his money at a time when he could not draw on a profession of philanthropic experts. Painstakingly thorough, Gates combined moral passion with great intellect. He spent his evenings bent over tomes of medicine, economics, history, and sociology, trying to improve himself and find clues on how best to govern philanthropy. Skeptical by nature, Gates saw a world crawling with quacks and frauds, and he enjoyed grilling people with trenchant questions to test their sincerity. Outspoken, uncompromising, he never hesitated to speak his piece to Rockefeller and was a peerless troubleshooter.

For some details on Rockefeller’s philanthropic successes, see here.