Baltasar (sometimes called Isaac de Castro), a celebrated Spanish Jew, born in the early part of the seventeenth century, and educated in Judaism by his parents, who outwardly professed themselves Catholics. Orobin studied the scholastic philosophy as taught in Spain, and became so skilled in it that he was appointed professor of metaphysics in the university of Salamanca. Afterwards, however, having applied himself to the study of physic, he practised that art with success at Seville, till being accused of Judaism, he was thrown into the prison of the Inquisition, and suffered the most dreadful cruelties, in order to extort a confession. After a confinement of three years, the inquisitors, finding themselves baffled by his perseverance in denying his religion, ordered his wounds to be cured, and discharged him. As soon as he had obtained his liberty, he proceeded to France, and was made professor of physic at Toulouse. He resided for some time in this city, still outwardly professing the Catholic religion; but at last, weary of dissembling, he repaired to Amsterdam, where he was circumcised, took the name of Isaac, and professed Judaism, still continuing, however, to practise physic, in which he was much esteemed. Upon the publication of Spinoza's work, he is said to have soon discovered the weak points in the system of the great pantheist; and when Bredenburg's answer to it appeared, Orobin, being persuaded that the writer, in refuting Spinoza, had also admitted some principles which tended to atheism, took up his pen against both, and in 1684 published a piece entitled Certamen Philosophicum, characterized by great acuteness and power. But the dispute in which he engaged with the celebrated Philip Limborch against the Christian religion made the greatest noise. In this he exerted the utmost force of his metaphysical genius, and conducted himself with great temper. The three papers which he wrote on the occasion were afterwards printed by his antagonist in an account which he published of the controversy, under the title of Amica Colloquio cum Judeo. Orobin died in 1687. (See Israel Aranged, translated and answered by Dr M'Caul, 8vo, London, 1839.)