A linguistic unity and national pride was developing. London English became the norm and predominated over rural dialects. Important news was announced and spread by word of mouth in market squares and sometimes in churches. As usual, traders provided one of the best sources of news; they maintained an informal network of speedy messengers and accurate reports because political changes so affected their ventures. News also came from peddlers, who visited villages and farms to sell items that could not be bought in the local village. These often included scissors, eyeglasses, colored handkerchiefs, calendars, fancy leather goods, watches, and clocks. Peddling was fairly profitable because of the lack of competition. But peddlers were often viewed as tramps and suspected of engaging in robbery as well as peddling. A royal post service was established by relays of mounted messengers. The first route was between London and the Scottish border, where there were frequent battles for land between the Scotch and English. The inland roads from town to town were still rough and without signs. A horseman could make up to 40 miles a day. Common carriers took passengers and parcels from various towns to London on scheduled journeys. Now the common yeoman could order goods from the London market, communicate readily with friends in London, and receive news of the world frequently. Trade with London was so great and the common carrier so efficient in transporting goods that the medieval fair began to decline. First the Grocers and then the Mercers refused to allow their members to sell goods at fairs. There was much highway robbery. Most goods were still transported by boats along the coasts, with trading at the ports. Embroidery was exported. Imported were timber, pitch, tar, potash [for cloth dying], furs, silk, satin, gold cloth, damask cloth, furred gowns, gems, fruit, spices, and sugar. Imports were restricted by national policy for the purpose of protecting native industries. English single-masted ships began to be replaced by two or three masted ships with high pointed bows to resist waves and sails enabling the ship to sail closer to the wind. 200 tuns was the usual carrying capacity. The increase in trade made piracy, even by merchants, profitable and frequent until merchant vessels began sailing in groups for their mutual protection. The astrolabe, which took altitude of sun and stars, was used for navigation. Consuls were appointed to assist English traders abroad. Henry IV appointed the first admiral of the entire nation and resolved to create a national fleet of warships instead of using merchant ships. In 1417, the war navy had 27 ships. In 1421, Portsmouth was fortified as a naval base. Henry V issued the orders that formed the basic law of English admiralty and appointed surgeons to the navy and army.