A city 56 km. (35 miles) NE of Smyrna, in modern Turkey, with valuable trading contacts in the 1st cent. CE. When Paul visited Philippi he met and converted Lydia from Thyatira, a seller of purple goods (Acts 16: 14–15). The fourth of the seven letters in Rev. (2: 18–29) was addressed to the Church in Thyatira.