Solomon ben Abraham Adret was one of the foremost Jewish scholars in the late 13th-early 14th century in Spain. He grew up in a wealthy family in Barcelona. His principal teachers were Jonah ben Abraham Gerondi and Nachmanides, who considered him to be his outstanding student.
As a young man, Adret became involved in financial deals; the king of Aragon was one of his debtors. He soon got out of business and focused on being the chief rabbi of Barcelona, a title he held for more than forty years.
He was a recognized Halachic authority, and he wrote more than 1,000 responsa to communities around the Jewish world including Germany, France, Bohemia, Sicily, Crete, Morocco, Algiers, Palestine, and Portugal. He thus bridged the Sephardic and Ashkenazic worlds. Many of his responsa influenced Joseph Karo and are the Halachah stated in the Shulchan Aruch.
He was known by the acronym RaSHBa.
Many of his responsa dealt with explaining difficult Biblical passages. Others dealt with communal matters. Adret was instrumental in helping organize the Jewish communities and their institutions.
He wrote Jewish defenses against accusations formulated by Church members. He brought relative communal stability to Spain.
Adret opened a yeshiva which attracted top scholars from around the world. He wrote commentaries to seventeen tractates of the Talmud and legal manual called Torat HaBayit, which dealt with practical ritual observance.
Besides being a Halachist, Adret was well-versed in philosophy and science.
Although a traditionalist, believing in the literal meaning of Torah, he was also concerned that the mystical influences were corrupting Judaism as well. He strongly attacked the activities of Abraham Abulafia, but he also attacked the secularists who forsook Torah study for science.
During the bitter Maimonidean Controversy, Adret sided with those opposed to the reconciliation of Divine Revelation with Rational Philosophy, but he felt they went too far in wanting to ban all study of science. He offered an acceptable compromise. In 1305, he wrote his famous ban: Jews could study astronomy and medicine at any age. Jews could study physics and metaphysics (philosophy) after the age of twenty-five. The Guide For the Perplexed could be studied by mature adults.
Sources: Gates to Jewish Heritage