Leonard Leo, who helped to choose judicial nominees for former President Donald Trump, obtained a historic $1.6 billion gift for his conservative legal network via an introduction through the Federalist Society, whose tax status forbids political activism.

Leo first met Barre Seid, the now 91-year-old manufacturing magnate turned donor, through an introduction arranged by Eugene Meyer, the longtime director of the Federalist Society. At the time, Leo was the society’s executive vice president, and he is currently its co-chair. Meyer envisioned Seid as a contributor to the society, according to a person familiar with the introduction. Instead, Leo cultivated Seid as a funder of his own dark money network. The result was a $1.6 billion gift announced last year — which is believed to be the largest political donation ever.

The unusual arrangement in which Leo met his top donor through the prestigious Federalist Society — which describes itself as a nonpartisan educational organization — suggests closer ties between the society and Leo’s activist network than previously known. Leo has used the dark money network to donate millions of dollars to the society and to pay at least $1.54 million to one Federalist Society employee and $775,000 to an entity run by another, according to federal disclosure forms.