Question: When did Yevdokiya Saburova's husband die?
Sentence (from "Tsarevich Ivan Ivanovich of Russia"): Ivan Ivanovich (Ива́н Иванович) (28 March 1554 – 19 November 1581) of the House of Rurik, was a Tsarevich (heir apparent) of Russia.
Relevant evidence: Yes