Complex sentence: The translations were enthusiastically reviewed by important literary magazines, including The Gentleman's Magazine, and published in Fraser's Magazine but there was some criticism that he had strayed from the original meaning, which Medwin had intentionally done when he felt the occasion demanded.
Split into simpler sentences: The translations were enthusiastically reviewed by major literary magazines, including The Gentleman's Magazine, and published in Fraser's Magazine. Some criticized him for straying from the original meaning, which he had intentionally done where he felt the occasion demanded.