Short answers, pulled from the story.
Sunni Islam gained political significance in 656 CE following the murder of the third caliph Uthman. The phrase sunnah became a rallying cry during the Battle of Siffin when Malik al-Ashtar encouraged resistance against Muawiya.
Abu al-Hasan al-Ashari lived between 873 and 935 and founded the Ashari theological school. This school stressed divine revelation over human reason and rejected the Mu'tazili position that Quranic references to God's attributes were metaphorical.
The four recognized Sunni schools of law are Hanafi, Maliki, Shafi'i, and Hanbali. These schools emerged from historical debates and were officially reaffirmed by the Ottoman Empire as a reaction to the Shiite character of the Persian Safavids.
The Arabic word sunna means the right path that has always been followed and dates back to pre-Islamic language. It later received connotations critical of Shi'i doctrines during the second Civil War between 680 and 692.
The Great Mosque of Kairouan located in Tunisia served as an important center of Islamic learning from the 9th to 11th century. The mosque emphasized the Maliki Madhhab during this period of significant Islamic scholarship.