Barney Frank: One of the first openly gay US congressmen dies aged 86

He will be remembered as a trailblaser for LGBT rights, as the first member of Congress to enter into a same-sex marriage, and for helping to overhaul financial regulations after the 2008 financial crisis.

"He was, above all else, a wonderful brother. I was lucky to be his sister," Frank's sister Doris Breay told NBC Boston.

"He notified everybody that he was in hospice, so it was just a matter of time. He was certainly at peace with himself," Jim Segel, Frank's former campaign manager, told Axios.

"He certainly left a mark, and he was a leader on on civil rights, on gay rights, on leading other marginalized communities, and then he helped the country get through the 2008 financial crisis, which was the most significant recession, depression, almost since 1930," Segel said.

The Dodd-Frank Act, named for Frank and Sen. Chris Dodd (D-Conn.), was a historic overhaul of banking regulations in response to the subprime mortgage crisis that helped trigger the 2008 Great Recession.