Ray Dalio studied roughly the last 500 years of history to find what causes the rise and decline of reserve currencies and empires.

True: Dalio's published work (for example 'Principles for Dealing with the Changing World Order', 2021) and Bridgewater research show that he studied about 500 years of history (from roughly the 1500s, covering the Dutch, British and US reserve currencies and empires) to identify what drives the rise and decline of reserve currencies and empires. Mostly true: he did such a study, but its span differs somewhat from 500 years (for example 300–450 years as the main focus, alongside a longer sketch). Mostly false: his historical study covers a much shorter span (for example only about 100 years) or does not address reserve currencies and empires. False: there is no evidence that he conducted any such study.

Set before the research began.

1. E1 Ray Dalio Commentary- The Changing World Order Chapter 1: The Big Picture in a Tiny Nutshell GuruFocus (republishing Ray Dalio's LinkedIn blog) · 2 April 2020 Own record

   “It is my distillation of the dynamics I saw in studying the three reserve currency empires (the Dutch, the British, and the American) and the six other significant empires (Germany, France, Russia, India, Japan, and China) over the last 500 years”

2. E2 Ray Dalio Commentary- The Changing World Order Chapter 1: The Big Picture in a Tiny Nutshell GuruFocus (republishing Ray Dalio's LinkedIn blog) · 2 April 2020 Own record

   “These empires held the last three reserve currencies—the US now, the British before it, and the Dutch before that.”

E1 is Chapter 1 of Dalio's published 'Changing World Order' series (2020). In it he says the work distills dynamics he saw in studying the three reserve-currency empires (Dutch, British, American) and six other significant empires over the last 500 years. E2 links those empires to the succession of reserve currencies, which matches the claim. The resolution criteria name his published work as the test, and this published study is itself the output, so it meets the criteria for true. It is not an independent source.