Dutch, like many other Indo-European languages, has gradually moved its nominal morphology from synthetic to chiefly analytic. It has retained some vestiges of the original case system, more so than English, but to a much lesser extent than German. In modern Dutch, nouns and articles are no longer inflected for case, although an elaborate case system was used in the written language until the middle of the 20th century. In addition, many surnames, toponyms and set expressions still exhibit fossilised inflected forms of the article and noun. Middle Ages In Middle Dutch, a productive case system was still in existence, which was very similar to that of modern German. Given below is the so-called "strong" inflection. (adjective clein = small, noun worm = worm, daet = deed/action, broot = (loaf of) bread) 16th to 18th centuries It was already observed in the 15th century that there existed no distinction between the nominative and accusative forms of nouns and articles in the northern dialects. From the Renaissance onward, the view that the Dutch language should somehow be 'ennobled' with an extensive case system after the model of Latin was widespread. Hendrik Louwerisz. Spieghel, an influential 16th-century grammarian, tried to reform and standardize the Dutch case system in his book on grammar, Twe-spraack van de Nederduitsche Letterkunst [Dialogue on the Low German art of letters] (1584). In particular, Spieghel wanted to create a distinction in grammatical function between two existing forms of the definite article, de and den, having de pertain to subjects and den to objects. (In this system, no distinction was made between masculine and feminine nouns, as was later done; des vrouws, den vrouwe (f) would stand alongside des heers, den here (m).) Another artificial distinction, still in use today, between the plural personal pronouns hun (for the indirect object) and hen (for the direct object) was created by Christiaen van Heule, who wrote De Nederduytsche spraec-konst ofte tael-beschrijvinghe [The Low German speech-art or language-description] (printed in 1633). In the same vein, the distinction between masculine and feminine nouns was rigidly maintained, although this distinction was felt only vaguely at best in the northern dialects. (In the dialects of the Southern Netherlands, however, the distinction did indeed exist and is still in existence today.) Celebrated poets such as Joost van den Vondel and Pieter Cornelisz. Hooft often disagreed in assigning gender to nouns, which they arbitrarily based on equivalents