I’m guessing that here means the current USA, the most likely reason is that the Ericsson’s did not have the man power or the financial backing that the Britain, Spain and France had. Also the Time period, during Liefs time the current Europe was divided into many, many in-United small kingdoms and clans, unlike Christopher Columbus’s time. And last but not least the new technology of better, bigger boats and guns helped the size of the exploits.