Born in Jerusalem on Dec. 24, 1927, Dorothea Noelle Naomi Porter was raised in Damascus, Syria. In 1953 she married Robert Porter, an economist attached to the British Embassy in Lebanon. As a diplomat's wife in the early 60's, Ms. Porter traveled to Iran and Jordan, spent holidays in Italy and France. Her marriage ended in 1964, and Thea opened a shop selling textiles collected during her travels. In 1971 Michael Butler, the producer of ''Hair'' on Broadway, financed a shop for Ms. Porter in New York. When the enterprise failed, Ms. Porter returned to England and turned her hand to decoration. Her store, Thea Porter Decorations, eventually went into receivership; she later formed a brief partnership in a smaller store with Princess Dina of Jordan.