After his training with Govinda, Shankara established his base in Varanasi (Kashi), the eternal city on the Ganges. Here he began writing his masterwork commentaries—the Brahma Sutra Bhashya, commentaries on ten principal Upanishads, and his Bhagavad Gita Bhashya. Varanasi witnessed the development of Advaita Vedanta's systematic philosophy. According to tradition, Shankara encountered Lord Shiva himself disguised as an outcaste (chandala) carrying a dog. When Shankara's disciples asked the chandala to move aside, the outcaste challenged: "If all is Brahman, what should move—the body or the Self?" Recognizing Shiva, Shankara immediately composed the Manisha Panchakam, acknowledging that caste distinctions are ultimately illusory—a remarkable social position for 8th century India.