Five years after the death of Aretha Franklin, a battle over her estate is ongoing.

A probate court trial involving three of her four sons began Monday in Michigan after Franklin failed to leave behind a typed estate plan.

The Queen of Soul died in 2018 at age 76 from a rare form of cancer.

More than one will

At the heart of the legal dispute are two separate wills.

Shortly after Franklin's death, her niece, Sabrina Owens, who at the time was the representative for the estate, found multiple, handwritten wills by the singer in her suburban Detroit home.

One of the documents was found under a couch cushion, while another was in a locked cabinet.

Two of her sons, Kecalf Franklin and Edward Franklin, want the document dated March 31, 2014 to be determined as her legal will, while another son, Ted White II, is advocating that a document from 2010 should stand.

Franklin's fourth son, Clarence Franklin, has special needs, is under legal guardianship and not involved in the case.

What's at stake

The brothers are seeking a legal determination of the distribution of the late singer's estate, including music royalties, cash, jewelry and property.

"The 2010 document calls for that plum property to be owned equally by Ted and Kecalf. The latter would be required to take business classes and, along with Ted, must provide a '1st class home for Edward,'" the papers state, according to the Detroit Free Press. "The 2014 document, on the other hand, gives that Bloomfield Hills house solely to Kecalf. Unlike his older brothers, he'd made a big family with two daughters and two sons — Aretha's grandchildren."

Why it's taken so long

Things were hampered in part by the pandemic, which found many legal cases being put on hold as courtrooms shifted to virtual hearings.

The Franklin family was unable to mediate a solution during the probate process, which led to the trial.

Don Wilson, a Los Angeles based entertainment lawyer who represented Franklin for almost three decades, told NBC News that the case could have been avoided had Franklin followed his advice to her that she have a will and trust set up prior to her death.

"We insisted that she have a will and a trust as part of her estate planning. But she was a very private person and I think she didn't want to share that information with another individual, such as an attorney," he said. "I think that's why, for the longest time, she didn't go into someone's office and do formal planning. She went ahead and wrote them up herself."

Franklin was known to generally insist on being paid in cash that she put in her purse and carried on stage with her during her performances.

CNN has reached out to the attorneys for Franklin's sons for comment.