Suggest alternative word for poetic line [closed]

The line currently reads "I did what must be done." Unfortunately, must is not really a past tense form. Can anyone suggest a substitute that maintains the meaning and the iambic trimeter of the line?

You have some options, but the tone changes a bit.

• I did what needed done.

• I did what was required.

Perhaps even

• I did what would be done.

As in “I did the thing that was destined/expected to be done.”