This Friday marks the one-year anniversary of Prince's death -- a day that will see Minnesota turn purple to honor the legendary singer and his impact on the music industry.

On April 21, 2016, Prince was found dead in an elevator at Paisley Park, after an accidental overdose on the painkiller Fentanyl. He was 57.

Here's a timeline of some of the key events in the singer's last two weeks:

April 7 - Dr. Michael Schulenberg, a Minnesota primary care physician, visits Prince, according to a search warrant. Also, two Prince concerts in Atlanta are postponed. The artist said at the time he had fallen ill with the flu.

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April 14 - Prince performs makeup concerts in Atlanta, apologizing to fans. He jokes about having been "under the weather," giving a slight smile. His voice seems a bit weak at times while speaking, but fans say he sounds fine when singing during his 80-minute show.

April 15 - Prince becomes ill on a flight home from Atlanta, and the plane makes an emergency stop in Moline, Illinois. A law enforcement official who spoke to the AP on condition of anonymity because he was not authorized to speak to the media said that Prince was found unconscious on the plane and that first responders gave him a shot of Narcan, an antidote used to reverse suspected opioid overdoses.

April 16 - Prince hosts a dance party at his Paisley Park complex and makes a brief appearance, showing off a new purple piano. "Wait a few days before you waste any prayers," he tells fans.

April 20 - Prince is seen by Schulenberg again, according to the warrant. At some point, Schulenberg prescribed Clonidine, Hydroxyzine Pamoate and Diazepam to Prince and ordered tests related to the singer's hip pain. Prince's close friend Kirk Johnson visits a Walgreens in Minnetonka to pick up the prescriptions.

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April 20 - Dr. Howard Kornfeld, a California addiction specialist, is asked by Prince representatives to help the star, according to Kornfeld attorney William Mauzy. Kornfeld sends his son, a non-physician, on a red-eye flight to Minnesota, carrying a drug used to treat opiate addiction.

April 21 - Andrew Kornfeld and others find Prince unresponsive in an elevator at Paisley Park. Schulenberg arrived "on the death scene" at some point, according to the warrant. He tells a detective he was there to drop off test results, and that he had prescribed medications that were to be filled at a Walgreen's pharmacy.