Background: "Hound Dog" is a twelve-bar blues song written by Jerry Leiber and Mike Stoller. Recorded originally by Willie Mae "Big Mama" Thornton on August 13, 1952, in Los Angeles and released by Peacock Records in late February 1953, "Hound Dog" was Thornton's only hit record, selling over 500,000 copies, spending 14 weeks in the R&B charts, including seven weeks at number one. Thornton's recording of "Hound Dog" is listed as one of the Rock and Roll Hall of Fame's "500 Songs That Shaped Rock and Roll", and was inducted into the Grammy Hall of Fame in February 2013. "Hound Dog" has been recorded more than 250 times. The best-known version is the July 1956 recording by Elvis Presley, which is ranked number 19 on Rolling Stone magazine's list of the 500 Greatest Songs of All Time; it is also one of the best-selling singles of all time.
Context: Their requests for payment having been ignored, Robey and two other music publishers initiated unprecedented legal proceedings in April against the record companies that released these competing songs, alleging copyright infringement. As a result, Chess Records withdrew Brim's "Rattlesnake" from sale. In the Memphis courts, Lion Publishing Co. sought royalties and treble damages, claiming "Bear Cat" was "a dead steal". In May, Phillips responded: "There's a lot of difference in the words. As for the tune, there's practically no melody, but a rhythm pattern", adding that it is hard to differentiate between any two 12-bar blues songs. By June 1953 in a "precedent-setting" decision the Court ruled against Phillips, and upheld the charges of plagiarism, finding the tune and some of the lyrics of "Bear Cat" to be identical to those of "Hound Dog". Phillips was ordered to pay 2% of all of the profits of "Bear Cat" plus court costs. As this amounted to $35,000 compensation, Phillips was reduced to near bankruptcy, ultimately forcing him to sell Elvis Presley's Sun contract to RCA for $35,000 to raise the funds to settle his debts. On June 4, 1953, Jet reported that: "The Sun Record Company of Memphis agreed to pay $2,080 to a Texas Recording firm because its blues tune, Bear Cat, is too similar to Hound Dog. Lion Publishing Company of Houston, Tex., won the out-of-court settlement after contending in a court suit that Bear Cat was a "conscious imitation" of their own recording with "only minor variations." Sam C. Phillips of Sun Record agreed to pay Hound Dog owners two cents per record for 79,000 waxings of Bear Cat already sold and two cents a record for future sales. On July 8 Robey wrote to Phillips again, thanking him "kindly for your co-operation in this matter", but Phillips still refused to purchase a mechanical license for Thomas' "Bear Cat". Robey then instructed his company lawyer Irving Marcus to sue Phillips and Sun Records, hoping to use this as a test case to determine the legal status of all answer songs. While earlier pressings of Sun 181 bore the caption "(The Answer To Hound Dog)" above the A-side title, as a result of the legal action this was removed from all later pressings. In the 1980s, Sam Phillips conceded: "I should have known better. The melody was exactly the same as theirs, but we claimed the credit for writing the damn thing". CANNOTANSWER
Question: When did the proceedings begin?

Answer:

By June 1953 in a "precedent-setting" decision the Court ruled against Phillips, and upheld the charges of plagiarism,