During the conflict of 1180, on the orders of their elder brother Roman, who had fled to the Polovtsians, Igor and Svyatoslav led the defense of Principality of Ryazan as the troops of the Grand Principality of Vladimir-Suzdal led by Vsevolod Yuryevich approached. Ryazan was not taken, but the dispute was settled by Roman and Igor complying with Vsevolod Yuryevich's desires, according to which the Princes of Ryazan were seated according to their seniority. After the settlement, (in 1186) Svyatoslav was mentioned as co-ruler with Vsevolod Glebovich in the Principality of Pronsk.
In 1186, Roman invited Vsevolod Glebovich and Svyatoslav to a council, but after their refusal, he began military actions and besieged Pronsk. When news of the arrival of troops from the Grand Principality of Vladimir-Suzdal and the Principality of Murom reached Kolomna, the troops of Ryazan lifted the siege of Pronsk, and Vsevolod Glebovich went to the troops from the Grand Principality of Vladimir-Suzdal with this news. However, after the opponents returned home, the troops of Ryazan marched again against Pronsk and cut the city's water supply. Svyatoslav opened the gates for them and received the rule of the Principality of Pronsk from Roman. Vsevolod Glebovich's troops, as well as the garrison of the Grand Principality of Vladimir-Suzdal were taken prisoners by the troops of the Principality of Ryazan. Vsevolod Glebovich was entrenched in Kolomna and participated in the new campaign of Vsevolod Yuryevich and the Princes of Murom against Ryazan in the same year. Vsevolod Glebovich returned to Principality of Pronsk, where he died in 1207 .
In 1207, Svyatoslav together with Roman and nephews Ingvar and Yuri Igorevichi were accused before Vsevolod Yuryevich by nephews Gleb and Oleg Vladimirovich in secret union with Olgovichi and ended up in captivity in Vladimir, Russia, during which he died.
Brothers and sisters
- Andrei Glebovich of Ryazan (c1150-c1185) - Prince of Ryazan.
- Roman Glebovich of Ryazan (c1152-1216) - Prince of Ryazan
- Igor Glebovich of Ryazan (c1154-1194) - the appanage prince of Ryazan.
- Feodosya Glebovna of Ryazan (c1156-c1200) - married Mstislav Rostislavich the Brave 
- Vladimir Glebovich of Pronsk (c1158-c1186) - Prince of Pronsk (1180-1186).
- Vsevolod Glebovich of Pronsk (c1160-1207) - the Prince of Pronsk (up to 1186, 1188-1207) and Kolomna (1186-1,188).
- Yaroslav Glebovich of Ryazan (c1164-c1199) - the prince of Ryazan.
Information about the wife of Svyatoslav missing.
According to the late chronicles, Svyatoslav had two sons, whose names are indicated differently in the sources :
- Rostislav (Yaroslav) Svyatoslavich (c1180-c1190)
- Mstislav Svyatoslavich (c1182-1210)
|Offspring of Svyatoslav Glebovich (Святослав Глебович князь рязанский) and unknown parent|
|Rostislav Svyatoslavich (c1180-c1190)||1180||1190|
|Mstislav Svyatoslavich (c1182-c1210)||1182||1210|