For the last two decades, Acumen has used philanthropic capital and leveraged the power of markets to solve problems of poverty. When we began in 2001, the term ‘impact investing’ did not yet exist; now it is part of the capital firmament. Acumen has evolved as well over that time; our approach is now less novel, but no less urgent. We chose to use this milestone as an opportunity for self-reflection, to discover where we (and other patient capital providers) have built new markets and influenced impact investing, but also where we have made mistakes or lost our way. In a conversation that combines data, reflections, and anecdotes from Acumen’s past, we will discuss how patient capital has enabled impact to thrive, where we and others have fallen short and what we can learn from those moments, and our vision for the future of patient capital over its next twenty years.