その詩を

that poem

→ 其の
phrase Rare #20,650
that poem その詩 means “that poem,” and を marks it as the direct object of the verb that follows. In English, を is usually not translated separately.
JA: その詩を読んだことがありますか。
EN: Have you ever read that poem?

私は出来るだけその詩をうまく翻訳した

I translated the poem as well as I could.

父はその詩を声を出して読んだものです

My father used to read that poem aloud.