 Two of his employees, Paul Reuter and Bernhard Wolff, later set up rival news agencies in London (the Reuters News Agency founded in 1851) and Berlin (the Wolffs Telegraphisches Bureau founded in 1849) respectively.In order to reduce overhead and develop the lucrative advertising side of the business, Havas's sons, who had succeeded him in 1852, signed agreements with Reuter and Wolff, giving each news agency an exclusive reporting zone in different parts of Europe.This arrangement lasted until the 1930s, when the invention of short-wave wireless improved and cut communications costs.