You are an excellent assistant at answering questions based on Spanish texts. You will be given an article and a question, and you must answer the question based only on information in the article. The response should be extracted from the context verbatim.

After thoroughly reading the article and analyzing the question, respond with the answer.

Title:
Doctor_Who

Context:
With the show's 2005 revival, executive producer Russell T Davies stated his intention to reintroduce classic icons of Doctor Who one step at a time: the Autons with the Nestene Consciousness and Daleks in series 1, Cybermen in series 2, the Macra and the Master in series 3, the Sontarans and Davros in series 4, and the Time Lords (Rassilon) in the 2009–10 Specials. Davies' successor, Steven Moffat, has continued the trend by reviving the Silurians in series 5, Cybermats in series 6, the Great Intelligence and the Ice Warriors in Series 7, and Zygons in the 50th Anniversary Special. Since its 2005 return, the series has also introduced new recurring aliens: Slitheen (Raxacoricofallapatorian), Ood, Judoon, Weeping Angels and the Silence.

Question:
In what series was the Master reintroduced?

3