Prince left on a high note with HitnRun Phase Two, an album of throwback R&B that recalled his mid-career sound and chart successes of the early '90s. But it wasn't entirely the result of third-act creativity, so much as Prince's unerring ability to mix and match current material with key tracks from his prodigious vault.

"All the musicians that played on this, they go, 'He just records and he puts it in the vault,'" Prince told Ebony in 2015. "All of them have stories: 'He's recording stuff you would not believe. He just threw it away.' I didn't throw it away. It just has to be on the right project – and all of these fit together now."

HitnRun Phase Two arrived on Dec. 12, 2015 with six songs believed to have been recorded in early- to mid-2015 at Paisley Park Studios. Four others had already trickled out as singles, some as long ago as 2011. "Black Muse" and "When She Comes" reportedly dated back even further.

"Big City," with its Sly Stone-style utopian triumphalism, "Extraloveable" and the James Brown-ish "2 T., 2 D." were from 2011; "Groovy Potential," "Screwdriver" and "Rocknroll Loveaffair" – the latter of which ranks as one of this set's brightest, sexiest moments – were begun in 2012. He'd already released "Baltimore" – a song Prince wrote after Freddie Gray died in police custody – and "Stare," among others, and already performed songs like the Isley Brothers-influenced "Revelation" in concert. Over time, the names changed on two songs, as "Extraloveable" became "Xtraloveable" and "Rock and Roll Love Affair" was rechristened "Rocknroll Loveaffair."

Still, considerable buzz built up around HitnRun Phase Two, which made a surprise premiere on the Tidal streaming service just a few months after Phase One. The album went on to become a Billboard Top 40 smash, and barely missed soaring into the U.K. Top 20.

Listen to Prince Perform 'Baltimore'

He earned it by deftly blending new thoughts with old, finding common thematic threads while employing a furious attention to detail. Prince was particularly proud of the way "Black Muse" led into "Revelation" on Phase Two. "You know, where else would ["Black Muse"] go except there?" he told Ebony. "But before, I had that whole song starting another album sequence – and it didn't work. So now, where it's placed, it's right where you wanna be at that point on the album."

The results relied more on horns than guitars, and skipped his recent focus on electronics. After a couple of rangy projects where he sometimes sounded like he was trying too hard, Prince returned to his soul strengths – even adding a quick reference to his chart-topping 1986 single of the same name after asking "Can I get a kiss?" on "Stare." He sounded like Prince again.

Then tragedy struck. His lyric from "Black Muse" – "you know we're built to last" – proved to be sadly untrue. The album's final moments on "Big City" suddenly became poignant: Prince stops singing as the song reaches its last brass blast, then adds, "That's it." Almost 50 seconds of empty silence follows before the track officially ends.

Phase Two finally arrived in physical form in January 2016, as Prince gave away the album during a weekend of shows at Paisley Park. He passed it out during the Australian and New Zealand legs of the Piano and a Microphone Tour too, before it finally garnered an official worldwide release in May 2016.

By then, Prince was already dead. HitnRun Phase Two reentered the Billboard R&B charts soon after, peaking 20 places higher at No. 3.