Strabo said that Pytheas gave an account of "what is beyond the Rhine as far as Scythia", which he, Strabo, thought was false. In the geographers of the late Roman Republic and early Roman Empire, such as Ptolemy, Scythia stretched eastward from the mouth of the river Vistula; thus Pytheas must have described the Germanic coast of the Baltic Sea; if the statement is true, there are no other possibilities. As to whether he explored it in person, he said that he explored the entire north in person (see under Thule above). As the periplus was a sort of ship's log, he probably did reach the Vistula.