"pete seeger didn't copywrite his version" Yes he did: "Wimoweh; adaptation and arrangement by Paul Campbell [pseud.]"

"'Wimoweh'... which Pete Seeger transcribed from a South African recording...." -- _World Telegram_, 1/11/50.

"To those songs which were published during the period between 1950 and 1953 we assigned the name 'Paul Campbell'...." -- _The Weavers Song Book_, copyright 1960.

The "enlargements of fragments of otherwise forgotten songs" by "Paul Campbell" in that song book included "When The Saints Go Marching In." Louis Armstrong was already famous when he recorded "When The Saints Go Marching In" in 1938, two years after the song was included in the hit Warner Brothers film The Green Pastures (which was mentioned by name in _Newsweek_ in 1936 when discussing Warner Brothers' recent strong earnings). The Golden Gate Quartet were also famous when they recorded it, also in 1938 (reissued with a different flipside in 1948). Mitchell's Christian Singers recorded it in 1938, Sleepy John Estes in 1941, Bunk Johnson in 1945, the Coleman Brothers in 1947, the Rainy City Jazz Band in 1947, Sidney Bechet in 1949. Wingy Manone (a popular white singer and trumpeter influenced by Armstrong) recorded it in 1939 and performed it for a '40s Soundie film. Uncle Rich Brown recorded it for the Library of Congress in 1940. Bob Wills played it on the radio in 1940. A band played it before General Patton in 1945. Graeme Bell's Australian Jazz Band were performing it by 1948, Sharkey Bonano by 1949, Kid Ory in 1949. The Golden Echoes recorded it for Specialty, The Five Trumpets for RCA Victor, and the Chuck Wagon Gang for Columbia, all in 1949. Armstrong performed it the 1947 Hollywood film New Orleans, and on both NBC-TV and CBS-TV in 1949. "Otherwise forgotten"?

And then there was the "Sylvie" that Leadbelly knew long before he met the Weavers, and they decided needed work...