Compounding the demands on the translator is the fact that no dictionary or thesaurus can ever be a fully adequate guide in translating. The British historian Alexander Tytler, in his Essay on the Principles of Translation (1790), emphasized that assiduous reading is a more comprehensive guide to a language than are dictionaries. The same point, but also including listening to the spoken language, had earlier, in 1783, been made by the Polish poet and grammarian Onufry Andrzej Kopczyński.[19]