Alan Rickman’s film resume includes many memorable characters, but his role as the intimidatingly moody Professor Severus Snape in the Harry Potter franchise remains one of his most iconic roles. Audiences may have enjoyed him as one of the most layered and pivotal characters in the movie franchise based on the JK Rowling novels, but in a collection of letters that were released for auction, there were moments where he didn’t enjoy Snape as much as we did.

The archive, which is auctioned off, is a collection of personal papers and letters that span his 40-year career as an actor.

In one particular letter, producer David Heyman wrote to him: “Thank you for making HP2 a success. I know, at times, you are frustrated but please know that you are an integral part of the films. And you are brilliant.”

The frustrations surfaced later in a note Rickman wrote while working on The Half-Blood Prince. In the note titled “Inside Snape’s Head,” Rickman wrote, “It’s as if David Yates has decided that this is not important in the scheme of things i.e. teen audience appeal.

In addition, the archive includes notes on how he developed close relationships with Rowling as well as Daniel Radcliffe. There are also heartwarming letters from actors including Kate Winslet, who starred with him in A Little Chaos as well as a note from Nicole Kidman who called his performance in the London production of Private Lives “inspiring.”

Rickman died at the age of 69 in 2016 from pancreatic cancer.