Whose patronus charm was the doe in Harry Potter 7 part 1?

The patronus charm that took the form of a doe in Harry Potter and the Deathly Hallows: Part 1 belonged to Professor Snape.

It's a crucial moment in the story, as it reveals Snape's deep and enduring love for Harry's mother, Lily. The doe is the same patronus Lily cast when she was young, and its appearance signifies Snape's ongoing protection and care for Harry.