In 1076 Sviatoslav sent reinforcements to Poland to help his son-in-law against the Bohemians. Sviatoslav died on 27 December 1077. The "Russian Primary Chronicle" writes that "the cutting of a sore" caused his death. He was buried in the Holy Savior Cathedral in Chernigov. Within a year, his elder brother Iziaslav was restored and Sviatoslav's sons lost most parts of his domains. According to the "Lyubetskiy sinodik", Sviatoslav's wife was Killikiya or Kelikia (Cecilia). On the other hand, German chroniclers write that his wife was Oda of Stade, a sister of Burchard, the Provost of Trier and she gave birth to one son. A portrait depicting Sviatoslav and his family in the "Izbornik of 1073" shows that he had five sons and four of them were adults at the time their portrait was made. Based on these sources, Sviatoslav married twice. According to Dimnik, Sviatoslav married his first wife, Killikiya between 1043 and 1047. Their first child seems to have been a daughter, Vysheslava. Her eldest brother Gleb became prince of Tmutorakan and later of Novgorod. The second son of Sviatoslav and Killikiya was Oleg, the future prince of Chernigov. Davyd, the future prince of Novgorod and Chernigov was born around 1051. Roman, who became prince of Tmutorakan, was born around 1052. Sviatoslav married his second wife, Oda of Stade in about 1065, according to Dimnik. Oda, the daughter of Lothair Udo I, Margrave of the Nordmark, was in some way related to Henry III, Holy Roman Emperor. She gave birth to Sviatoslav's fifth son, Yaroslav, who later became prince of Murom and Chernigov. After Sviatoslav's death, Oda and her son moved to the Holy Roman Empire.