that Ya'qubi, Kitab al-Buldan ("The Book of Countries", 889–890), also has a relevant passage. In a legendary story about a siege of the Tsanars in the Caucasus in 854, mention is made of "the overlords (sahib) of the Byzantines (al-Rum), of the Khazars, and of the Slavs (al-Saqaliba)", which Zuckerman connected with a supposed Rus' khagan. According to Zuckerman, Ibn Khordadbeh and other Arab authors often confused the terms Rus and Saqaliba when describing Caspian expeditions of the Rusʹ in the 9th and 10th centuries. But Ibn Khordādbeh's Book of Roads and Kingdoms does not mention the title of "khagan" for the ruler of Rus'. Old East Slavic sources The three later Old East Slavic sources mentioning a kagan (Hilarion of Kiev's 11th-century Sermon on Law and Grace, and the 11th-century Saint Sophia Cathedral, Kyiv inscription) or kogan (the 12th-century The Tale of Igor's Campaign) have generally been understood to refer to the ruler of Kievan Rus'. According to Halperin (1987), the title kagan in the Annales Bertiniani sub anno 839, Hilarion's Sermon, and in The Tale of Igor's Campaign all apply to "the ruler of Kiev". He agreed with Peter B. Golden (1982) that this reflected Khazar influence on Kievan Rus', and argued that the use of a "steppe title" in Kiev 'may be the only case of the title's use by a non-nomadic people'. Halperin also found it "highly anomalous" that a Christian prelate like Hilarion would 'laud his ruler with a shamanist title', adding in 2022: "The Christian ethos of the sermon is marred by Ilarion's attribution to Vladimir of the Khazar title kagan, which was definitely not Christian." Hilarion's Sermon on Law and Grace mentions the word kagan () throughout the text, a total of five times. и похвала каганоу нашемоу влодимероу, ѿ негоже крещени быхом ("And: an encomium to our kagan Volodimer, by whom we were baptized.") великааго кагана нашеа земли Володимера, вънука старааго Игоря, сына же славнааго Святослава ("the great kagan of our land Volodimer, the grandson of Igor' of old, and the son of the glorious Svjatoslav.") каганъ нашь Влодимеръ ("Volodimer, our kagan") Съвлѣче же ся убо каганъ нашь и съ ризами ветъхааго человѣка ("So our kagan cast off his clothing") Паче же помолися о сынѣ твоемь, благовѣрнѣмь каганѣ нашемь Георгии ("And furthermore, pray for your son, our devout kagan, Georgij";). Georgij was the baptismal name of Yaroslav the Wise, who reigned in