Environmental history of a river on the example of Slovak-Hungarian border river Ipeľ

The initian methodological part of the study deals with the environmental history as a new branch of science that is currently being developed arond the world. THe environmental history has stagnated in Slovakia, so the aim of this article is to contribute, at least partially, to the further development of this field of science. The second part of the paper present a case study, which on the basis of historical, archival and field research briefly focuses on the environmental history of the border river Ipeľ, forming the broder between Slovak Republic and Hungary since 1918. The river and its river basin had been transformaed by intensive human activities, which began in the 10th century.