MINNEAPOLIS - Prince's purple-clad fans were converging on Minnesota for a celebration of the pop legend one year after his sudden death, but discord over commercialisation of his legacy clouded the anniversary.
Prince's Paisley Park estate -- once mythically hermetic but opened since his death to paid tours -- was the centre of festivities with plans for concerts, panel talks and a dance party to the infectious funk of the "Purple Rain" star.
George Clinton, the 75-year-old whose popularisation of funk music in the 1970s helped pave the way for Prince, opened the ticketed "Celebration" at Paisley Park.
Bridges, stadiums and other landmarks in Minneapolis and adjacent St. Paul were being lit up purple for two nights in tribute to Prince, who despite his international fame had happily stayed in his hometown.
But Prince's commercial legacy remains mired in controversy. He died at age 57 from an accidental overdose of powerful painkillers and left no will or children, although dozens quickly came forward to claim they were heirs.
George Boxill, a sound engineer who worked with Prince, had arranged the release of the music recorded from 2006 to 2008 with the title track already out this week.
Putting the EP on an independent label, Boxill said he was respecting the wishes of the star who long battled the music industry and that most proceeds would go to the estate.
But the estate objected, accusing Boxill of seeking to profit and saying that he did not have the right to release the music on his own.
- Still a chart-topper -
Prince's music saw a massive increase in sales after his death. Nielsen Music, the tracking service behind the benchmark Billboard chart, said Thursday that Prince sold more than any other artist in 2016 when all albums are counted.
Prince sold 2.23 million albums last year in the United States, just above English balladeer Adele -- whose blockbuster album "25" came out in late 2015 -- at 2.21 million, Nielsen Music said.
Prince had sought ways to release music on his own and famously changed his name to an unpronounceable symbol and wrote "slave" on his cheek in the 1990s to protest the conditions set by label Warner.
Since his death his estate, led by his siblings, has teamed up with Warner which will reissue 1984's "Purple Rain," along with an accompanying album of unreleased music for Prince's birthday in June.
Prince's music also returned in February to major streaming services. Prince had only put his music out on rap mogul Jay Z's Tidal, through which he released his last two albums.
- Sudden death -
Prince -- an outward model of health who did not drink, advocated a vegetarian diet and admonished band members who used drugs -- had secretly battled an addiction to painkillers following a hip surgery.
He had sought help from a California specialist days before his death. Court documents unsealed this week showed that investigators found bottles of pills prescribed to his friends at Paisley Park.
A tribute concert to Prince took place in October in the 20,000-seat XCel Energy Center in St. Paul with his friend Stevie Wonder and dancer ex-wife Mayte Garcia among the performers.
Prince's sister Tyka Nelson and half-brother Omarr Baker later complained in court that an original administrator assigned to run the estate handled the tribute poorly and that it was meant to be a much larger affair.
Prince's estate and the professional administrators say they need to monetise his legacy just to stay afloat and handle tax bills without the pop singer alive to tour and otherwise make money.
Prince was one of a number of prominent musicians to die in 2016 including George Michael, Leonard Cohen and David Bowie -- whose "Heroes" Prince covered in a final concert.