duck. The Shetland pig, or grice, has been extinct since about 1930. The islands' motto, which appears on the Council's coat of arms, is "" (“By law shall the land be built"). The phrase is of Old Norse origin, is mentioned in Njáls saga, and was likely borrowed from provincial Norwegian laws such as the Frostathing Law. Etymology The name Shetland may derive from the Old Norse words ('hilt'), and ('land'). Another possibility is that the first syllable is derived from the name of an ancient Celtic tribe. In 43 CE, the Roman author Pomponius Mela made reference in his writing to seven islands he called the . In 77 CE, Pliny the Elder called these same islands the . Scholars have inferred that both of these references are to islands in the Shetland group. Another possible early written reference to the islands is Tacitus' report in Agricola in 98 CE. After he described the Roman discovery and conquest of Orkney, he added that the Roman fleet had seen "Thule, too". In early Irish literature, Shetland is referred to as — "the Isles of Cats" (meaning the island inhabited by the tribe called Cat). This may have been the pre-Norse inhabitants' name for the islands. Cat was the name of a Pictish people who occupied parts of the northern Scottish mainland (see Kingdom of Cat); and their name survives in the names of the county of Caithness and in the Scottish Gaelic name for Sutherland, , which means "among the Cats". The oldest known version of the modern name Shetland is ; this may represent "Catland", the Germanic language softening the C- to H- according to Grimm's law. It occurs in a letter written by Harald, earl of Orkney, Shetland and Caithness, in c.1190. By 1431, the islands were being referred to as Hetland, after various intermediate transformations. It is possible that the Pictish "cat" sound contributed to this Norse name. In the 16th century, Shetland was referred to as . Gradually, the Scandinavian Norn language previously spoken by the inhabitants of the islands was replaced by the Shetland dialect of Scots and became . The initial letter is the Middle Scots letter, yogh, the pronunciation of which is almost identical to the original Norn sound, . When the use of the letter yogh was discontinued, it was often replaced by the similar-looking letter z (which at the time was