Question: SV Werder Bremen won its first ever German double, clinching both Bundesliga and the DFB-Pokal, Werder lost both Aílton and defensive senior talisman Mladen Krstajić to Schalke 04, Krstajić is a former Serbian footballer who played as a centre back, born on which date?
Sentence (from "Mladen Krstajić"): He was known for his composure, leadership and defensive ability.
Relevant evidence: No