This obituary is part of a series about people who have died in the coronavirus pandemic. Read about others here.

He was just 15 when he joined the underground resisting the Nazis in what was then Czechoslovakia.

But Romi Cohn was resourceful enough to supply Jewish refugees with housing and furnish them with false Christian identifications, stamping them with German seals provided by a cooperative Gestapo source. In all, he saved 56 families, according to the Twitter account of Rep. Max Rose, his congressman on Staten Island, N.Y.

Mr. Cohn died of respiratory distress caused by pneumonia and the coronavirus on Tuesday at Maimonides Hospital in Brooklyn, his great-nephew, Shulem Geldzahler, said. He was 91 and had homes in Borough Park, Brooklyn, and Great Kills, Staten Island.

After the war, Mr. Cohn made his way to the United States and became wealthy developing thousands of single-family homes on Staten Island. He also turned himself into an expert mohel, performing thousands of circumcisions and writing scholarly articles. He even set up an operating theater in his Staten Island home to circumcise adult Russian Jews who had not been able to undergo the ritual as infants because of Soviet strictures.