Alan Rickman’s struggle with playing Professor Severus Snape in the “Harry Potter” franchise just became widely known thanks to his personal letters.

According to Yahoo!, Neil Pearson Rare Books is auctioning off Rickman’s old mementos, including his personal letters. The letters shed light on Rickman’s thoughts about playing Snape.

Rickman died in 2016 from cancer. He appeared in all eight “Harry Potter” films from 2001 to 2011.

One of the letters is from producer David Heyman, who thanked Rickman for his performance in “Harry Potter and the Chamber of Secrets.”

“Thank you for making HP2 a success,” the letter reads. “I know, at times, you are frustrated but please know that you are an integral part of the films. And you are brilliant.”

Meanwhile, the collection includes another note Rickman wrote while he was working on “Harry Potter and the Half-Blood Prince,” which was released in 2009.

The letter, titled “Inside Snape’s Head,” expressed frustration with how the film’s director, David Yates, treated Snape’s character in that film.

“It’s as if David Yates has decided that this is not important in the scheme of things i.e. teen audience appeal,” he wrote.

In 2011, Rickman’s thoughts about Snape’s portrayal on-screen came to light thanks to a Los Angeles Times report.

Rickman told the L.A. Times he considered the role “a punctuation mark” to his life “because I would be doing other things but always come back to that, and I was always aware of my place in the story even as others around me were not."

There’s also another letter between Rickman and J.K. Rowling, who wrote the “Harry Potter” books.

“Just back from weeks away and had to send a line about what you wrote in the souvenir programme for Hallows II. Made me very tearful. Thank *you* for doing justice to my most complex character,” Rowling wrote to Rickman.

Rickman also previously spoke about how Rowling trusted him with the role of Snape. Rowling revealed the meaning behind Snape’s “always” line — which revealed to audiences that Snape loved Harry’s mother, Lily — to Rickman before she finished the books, according to Entertainment Weekly.

“If you remember, when I did the first film, she’d only written three or four books, so nobody knew where it was really going except her,” he told HitFix in 2011, according to multiple reports. “And it was important for her that I know something, but she only gave me a tiny piece of information which helped me think it was a more ambiguous route.”