ca. 807

“Dress Code for Jews” Issued by Abbassid Caliph Harun al-Rashid [Persia; Present-day Iran/Iraq/Syria/North Africa] [Unconfirmed] 

Commentary from other sources:
1) “The Persian Abbassid Caliph Harun al-Rashid ordered Jews to wear a yellow belt.”
Bitton, Jimmy: “It’s Not 1938 Again;” jewishmag.com