Question

who is shankaracharya​

Answer 1

shankracharya was the Gagat guru

Answer 2

Shankaracharya (शङ्कराचार्य) (IAST: Śaṅkarācārya, Shankara acharya) is a commonly used title of heads of monasteries called mathas in the Advaita Vedanta tradition. The title derives from Adi Shankara, an 8th-century AD reformer of Hinduism. He is honored as Jagadguru, a title that was used earlier only to Krishna.