Voltaire took this opportunity to visit England. He had been acquainted with lord and lady Bolingbroke in France. He appreciated the talents of the illustrious Englishman, admired his various knowledge, and was fascinated by the charms of his conversation. Although he never appears to have at all understood the real foundations of English liberty, yet he appreciated its effects, especially at a moment when he was suffering so grievously from an act of despotism. Liberty of thought was in his eyes a blessing superior to every other. He read the works of Locke with enthusiasm; and while he lamented that such disquisitions were not tolerated in France, he became eager to impart to his countrymen the new range of ideas he acquired from the perusal. The discoveries of Newton also attracted his attention. He exchanged the frivolities of Paris for serious philosophy. He became aware that freedom from prejudice and the acquirement of knowledge were not mere luxuries intended for the few, but a blessing for the many; to confer and extend which was the duty of the enlightened. From that moment he resolved to turn his chief endeavours to liberate his country from priestly thraldom and antique prejudices. He felt his powers; his industry was equal to his wit, and enabled him to use a vast variety of literary weapons. What his countrymen deemed poetry, the drama, history, philosophy, and all slighter compositions, animated by wit and fancy, were to be put in use by turns for this great end. He published his "Henriade" while in England. It was better received than it deserved; and the profits he gained were the foundation of his future opulence. He wrote the tragedy of "Brutus," in which he imagined that he developed a truly republican spirit, and a love of liberty worthy of the Romans.