The history of journalism spans the growth of technology and trade, marked by the advent of specialized techniques for gathering and disseminating information on a regular basis that has caused, as one history of journalism surmises, the steady increase of "the scope of news available to us and the speed with which it is transmitted. Before the printing press was invented, word of mouth was the primary source of news. Returning merchants, sailors and travellers brought news back to the mainland, and this was then picked up by pedlars and travelling players and spread from town to town. Ancient scribes often wrote this information down. This transmission of news was highly unreliable and died out with the invention of the printing press. Newspapers (and to a lesser extent, magazines) have always been the primary medium of journalists since the 18th century, radio and television in the 20th century, and the Internet in the 21st century.