Question: What Persian general took advantage of Nasr ibn Sayyar being preoccupied with a civil war? 

Context articles: Sixth Siege of Gibraltar
Thimbron (fl. 400–391 BC)
Nasr ibn Shabath al-Uqayli
Thabit ibn Nasr
Rafi ibn al-Layth
Al-Harith ibn Surayj
Battle of Monte Laturce
Abu Muslim
Nasr ibn Sayyar
Kardarigan (7th century)

The Sixth Siege of Gibraltar in 1411 was the only occasion on which control of Gibraltar was contested between two Islamic powers.
 After the failed Fifth Siege of Gibraltar in 1349–50, which ended with the death of King Alfonso XI of Castile from bubonic plague, the Kingdom of Castile was preoccupied with the Castilian Civil War and its aftermath.
 In 1369, Sultan Muhammed V of Granada took advantage of the Castilians' distractions and in the Siege of Algeciras (1369) he seized the city of Algeciras, on the west side of the Bay of Gibraltar, which Alfonso XI had captured in 1344.
 After razing it to the ground he made peace with Henry II, the winner of the civil war.
 The truce was renewed by Henry's successors John I and Henry III.
 At some point during the truces, control of Gibraltar was transferred from the Marinid dynasty of Morocco, which had held it since 1333, to the Granadans.
 It is not clear why this happened; it may have been as a condition of the Granadans assisting the Marinids against rebels in Morocco.
Thimbron or Thibron (Greek: Θίμβρων ; fl.
 400–391 BC) was a Lacedaemonian general.
 He was sent out as harmost in 400 BC, with an army of about 5,000 men, to aid the Ionians against Tissaphernes, who wished to bring them into subjection.
 Thibron raised a substantial force of Peloponnesian troops and levies from other cities around Greece, but was initially unable to face the Persian army in the field.
 After he was joined by elements of the Ten Thousand, he challenged and defeated the Persian army on several occasions; seizing several cities before settling in to besiege Larissa.
 That siege proved fruitless, and Thibron was ordered to abandon it, and then replaced by another general, Dercylidas, before he could launch his next campaign.
 Upon his return to Sparta Thibron was tried and exiled for allowing his troops to plunder Sparta's allies in the region.
 In 391 BC, during the Corinthian War, Thibron was again dispatched to Ionia with an army, and was ordered to take aggressive action against the Persian satrap Struthas, who was pursuing a pro-Athenian, anti-Spartan policy.
 Thibron launched a number of successful raids into Persian territory.
 His raids tended to be poorly organized, however, and Struthas took advantage of this to ambush one of Thibron's raiding parties.
 The Spartans were routed, and a large number of them, including Thibron, were killed.
Nasr ibn Shabath al-Uqayli () was the leader of a rebellion of the Qays tribe in the Jazira against the central Abbasid government during the civil war of the Fourth Fitna.
Thabit ibn Nasr ibn Malik al-Khuza'i (died 813/14) was an Abbasid general and governor of the Cilician frontier zone ("al-thughur al-Sha'miya") with the Byzantine Empire in 808–813.
Rafi ibn al-Layth ibn Nasr ibn Sayyar was a Khurasani Arab noble who led a large-scale rebellion against the Abbasid Caliphate in 806–809.
Abu Hatim al-Harith ibn Surayj ibn Yazid ibn Sawa ibn Ward ibn Murra ibn Sufyan ibn Mujashi (Arabic: أبو حاتم الحارث بن سريج‎ ‎ ) was an Arab leader of a large-scale social rebellion against the Umayyad Caliphate in Khurasan and Transoxiana.
 Harith's rebellion began in 734 and represented the grievances of both the local Arab settlers as well as the native Iranian converts ("mawali"), who were not recognized as equal to the Arab Muslims, against the Umayyad regime.
 Harith based his revolt on religious grounds and won over a large part of both the Arab settlers and the native population, but failed twice to capture the provincial capital of Marw.
 The rebellion was finally suppressed by Asad ibn Abdallah al-Qasri in 736.
 Along with a few supporters, Harith managed to escape capture and allied himself with the heathen Turgesh.
 Harith accompanied the Turgesh "khagan" Suluk in his invasion deep into Arab territory, which was decisively beaten back in the Battle of Kharistan in 737.
 With Turgesh power collapsing thereafter, Harith remained in Transoxiana supported by the native princes.
 Asad's successor, Nasr ibn Sayyar, campaigned against Harith and his native supporters, but eventually, hoping to use him to bolster his position in the Arab intertribal rivalries, Nasr secured for Harith a pardon from the Caliph.
 Harith returned to Marw in 745.
 Soon however he raised a sizeable armed force and challenged Nasr's authority, until he was killed in a clash with his ally Juday' al-Kirmani in 746.
 His revolt weakened Arab power in Central Asia and facilitated the beginning of the Abbasid Revolution that would overthrow the Umayyads.
The Battle of Monte Laturce, also known as the second Battle of Albelda, was a victory for the forces of Ordoño I of Asturias and his ally García Íñiguez of Pamplona.
 They defeated the latter's uncle and former ally, the Banu Qasi lord of Borja, Zaragoza, Terrer, and Tudela, Navarre, Musa ibn Musa ibn Qasi, a marcher baron so powerful and independent that he was called by an Andalusi chronicler "The Third King of the Spains" ("Spaniae").
 The battle took place during the Asturian siege of a new fortress under construction by Musa at Albelda.
 The fortress was taken a few days after the battle.
 After Monte Laturce, Musa was forced to fully submit to the Emir of Córdoba, who took advantage of Musa's weakness to remove him as "wāli" of the Upper March, initiating a decade-long eclipse of the Banu Qasi.
Abu Muslim Abd al-Rahman ibn Muslim al-Khorasani or al-Khurasani (Arabic: أبو مسلم عبد الرحمن بن مسلم الخراساني‎ ‎ born 718-19 or 723-27, died in 755), born Vehzādān Pūr-i Vandād Hormoz (Persian: وهزادان پور ونداد هرمزد‎ ‎ ), was a Persian general in service of the Abbasid dynasty, who led the Abbasid Revolution that toppled the Umayyad dynasty.
Naṣr ibn Sayyār al-Lāythi al-Kināni (Arabic: نصر بن سيار الليثي الكناني‎ ‎ ; 663–748) was an Arab general and the last Umayyad governor of Khurasan in 738–748.
 Nasr played a distinguished role in the wars against the Turgesh, although he failed to decisively confront the rebellion of al-Harith ibn Surayj in its early stages.
 Although respected as a soldier and a statesman, he owed his appointment as governor more to his obscure tribal background, which rendered him dependent on the Caliph.
 His tenure was nevertheless successful, as Nasr introduced long-overdue tax reforms that alleviated social tension and largely restored stabilized Umayyad control in Transoxiana, which had been greatly reduced under the Turgesh onslaught.
 His last years were occupied by intertribal rivalries and uprisings, however, as the Caliphate itself descended into a period of civil war.
 In 746 Nasr was driven from his capital by Ibn Surayj and Juday' al-Kirmani, but returned after the latter fell out among themselves, resulting in Ibn Surayj's death.
 Preoccupied with this conflict, Nasr was unable to stop the outbreak and spread of the Abbasid Revolution, whose leader, Abu Muslim, exploited the situation to his advantage.
 Evicted from his province in early 748, he fled to Iran pursued by the Abbasid forces, where he died on 9 December 748.
Kardarigan (Greek: Καρδαριγάν ) was a Sassanid Persian general of the early 7th century, who fought in the Byzantine-Sassanid War of 602–628.
 He is usually distinguished from another Persian general of the same name who was active during the 580s.
 The name is actually an honorific title and means "black hawk".