ART Discussion – Early Christian, Byzantine and Gothic art

Please share your understanding of Early Christian, Byzantine and Gothic art. What was the purpose of artists in these time periods? What was their relationship to their religion? How did the art styles, materials and approaches change over time?
sources to use :

https://www.khanacademy.org/humanities/medieval-world/gothic-art/gothic-art-in-france/v/birth-of-the-gothic-abbot-suger-and-the-ambulatory-in-the-basilica-of-st-denis-1140-44
https://www.khanacademy.org/humanities/ap-art-history/early-europe-and-colonial-americas/medieval-europe-islamic-world/v/chartres-cathedral?modal=1
https://www.khanacademy.org/humanities/approaches-to-art-history/approaches-art-history/introduction-art-history/v/the-body-in-western-painting