Question: Who is the paternal grandfather of Shahrbanu?

Knowledge 1: Shahrbanu
Shahrbānū (or Shehr Bano) ("Lady of the Land") was allegedly one of the wives of Husayn ibn Ali, the third Twelver Shia Imam and grandson of the Islamic prophet Muhammad, as well as the mother of his successor, Ali ibnHusayn.She was reportedly a Sassanid princess, a daughter of Yazdegerd III, the last Sassanid emperor of Persia.Shahrbanu has also been referred to with several other names by different writers, such as: "ShaharbānawayhShahzanānShahjahanJahanshahSalāmaSalāfaGhazāla", and "Sādira".Islamic legends state that Shahrbanu was captured during the Muslim conquest of Persia.When presented before the Arab nobility and offered a choice in husband, she requested to be given in marriage to Husayn.The majority of Shia sources state that Shahrbanu subsequently died shortly after giving birth to her son Ali and was buried in the Jannat al-Baqi, alongside other members of Muhammad's family.Some traditions however, indicate to the Bibi Shahr Banu Shrine in Rey being her resting place.Shahrbanu is viewed as a saintly figure by both the Shia and Sunni denominations and is especially revered in Iran, her importance being partly tied to the link she provides between pre-Islamic Persia and modern Shi'ism.However, her historicity is uncertain.Islamic writers, such as al-Mubarrad, Ya'qubi and al-Kulayni, began alluding to Shahrbanu and her imperial Persian background from the 9th century onward.However, the earliest sources make no mention of the mother of Ali ibn Husayn, nor do they ascribe him with maternal royal ancestry.The first references were from Ibn Sa'd and Ibn Qutaybah, also in the 9th century, who instead describe her as being a slave from Sindh.This leads the Encyclopædia Iranica to consider that Shahrbanu was "undeniably legendary". [SEP] Knowledge 2: Yazdegerd III
Yazdegerd III (also spelled Yazdgerd III and Yazdgird III; ; New Persian:), was the last Sasanian King of Kings of Iran from 632 to 651.His father was Shahriyar and his grandfather was Khosrow II.Ascending the throne at the age of merely eight, the young shah lacked authority and reigned as figurehead, whilst real power was in the hands of the army commanders, courtiers, and powerful members of the aristocracy, who were fighting amongst themselves and wiping out each other.The Sasanian Empire was falling apart swiftly due to internal conflicts, and was at the same time also invaded on all fronts−bythe Turks in the east, and Khazars in the west.It was, however, the Arabs, united under the banner of Islam, who dealt the deadly blow to the empire.Yazdegerd was unable to contain the Arab invasion of Iran, and spent most of his reign fleeing from one province to another, in hopes of raising an army to repel the Arabs, which ultimately proved unsuccessful, with Yazdegerd meeting his end at hands of a miller near Marw in 651, thus bringing an end to the last pre-Islamic Iranian empire after more than 400 years of rule.
Knowledge 1: Shahrbanu
Shahrbānū (or Shehr Bano) ("Lady of the Land") was allegedly one of the wives of Husayn ibn Ali, the third Twelver Shia Imam and grandson of the Islamic prophet Muhammad, as well as the mother of his successor, Ali ibnHusayn.She was reportedly a Sassanid princess, a daughter of Yazdegerd III, the last Sassanid emperor of Persia.Shahrbanu has also been referred to with several other names by different writers, such as: "ShaharbānawayhShahzanānShahjahanJahanshahSalāmaSalāfaGhazāla", and "Sādira".Islamic legends state that Shahrbanu was captured during the Muslim conquest of Persia.When presented before the Arab nobility and offered a choice in husband, she requested to be given in marriage to Husayn.The majority of Shia sources state that Shahrbanu subsequently died shortly after giving birth to her son Ali and was buried in the Jannat al-Baqi, alongside other members of Muhammad's family.Some traditions however, indicate to the Bibi Shahr Banu Shrine in Rey being her resting place.Shahrbanu is viewed as a saintly figure by both the Shia and Sunni denominations and is especially revered in Iran, her importance being partly tied to the link she provides between pre-Islamic Persia and modern Shi'ism.However, her historicity is uncertain.Islamic writers, such as al-Mubarrad, Ya'qubi and al-Kulayni, began alluding to Shahrbanu and her imperial Persian background from the 9th century onward.However, the earliest sources make no mention of the mother of Ali ibn Husayn, nor do they ascribe him with maternal royal ancestry.The first references were from Ibn Sa'd and Ibn Qutaybah, also in the 9th century, who instead describe her as being a slave from Sindh.This leads the Encyclopædia Iranica to consider that Shahrbanu was "undeniably legendary". [SEP] Knowledge 2: Fujiwara no Nagara
, also known as Fujiwara no Nagayoshi, was a Japanese statesman, courtier and politician of the early Heian period.He was the grandfather of Emperor Yōzei.
Knowledge 1: Shahrbanu
Shahrbānū (or Shehr Bano) ("Lady of the Land") was allegedly one of the wives of Husayn ibn Ali, the third Twelver Shia Imam and grandson of the Islamic prophet Muhammad, as well as the mother of his successor, Ali ibnHusayn.She was reportedly a Sassanid princess, a daughter of Yazdegerd III, the last Sassanid emperor of Persia.Shahrbanu has also been referred to with several other names by different writers, such as: "ShaharbānawayhShahzanānShahjahanJahanshahSalāmaSalāfaGhazāla", and "Sādira".Islamic legends state that Shahrbanu was captured during the Muslim conquest of Persia.When presented before the Arab nobility and offered a choice in husband, she requested to be given in marriage to Husayn.The majority of Shia sources state that Shahrbanu subsequently died shortly after giving birth to her son Ali and was buried in the Jannat al-Baqi, alongside other members of Muhammad's family.Some traditions however, indicate to the Bibi Shahr Banu Shrine in Rey being her resting place.Shahrbanu is viewed as a saintly figure by both the Shia and Sunni denominations and is especially revered in Iran, her importance being partly tied to the link she provides between pre-Islamic Persia and modern Shi'ism.However, her historicity is uncertain.Islamic writers, such as al-Mubarrad, Ya'qubi and al-Kulayni, began alluding to Shahrbanu and her imperial Persian background from the 9th century onward.However, the earliest sources make no mention of the mother of Ali ibn Husayn, nor do they ascribe him with maternal royal ancestry.The first references were from Ibn Sa'd and Ibn Qutaybah, also in the 9th century, who instead describe her as being a slave from Sindh.This leads the Encyclopædia Iranica to consider that Shahrbanu was "undeniably legendary". [SEP] Knowledge 2: Kaya Alp
Kaya Alp was, according to Ottoman tradition, the son of Kızıl Buğa and the father of Suleyman Shah, who was, in turn, the grandfather of Ertuğrul, and the great grandfather of the Ottoman Empire founder, Osman I.

Answer: Shahriyar