I got a question for you: Ariel is a spirit who appears in William Shakespeare's play The Tempest. Ariel is bound to serve the magician Prospero, who rescued him from the tree in which he was imprisoned by Sycorax, the witch who previously inhabited the island. Prospero greets disobedience with a reminder that he saved Ariel from Sycorax's spell, and with promises to grant Ariel his freedom. Ariel is Prospero's eyes and ears throughout the play, using his magical abilities to cause the tempest in Act One which gives the play its name, and to foil other characters' plots to bring down his master.

Answer this question: where was ariel before prospero set him free?
Let's think first:
The important part for answering this question is: Ariel is bound to serve the magician Prospero, who rescued him from the tree in which he was imprisoned by Sycorax, the witch who previously inhabited the island.
Therefore, the answer is the tree in which he was imprisoned by Sycorax.