male line and Eric III was succeeded by his second cousin Eric IV of Saxe-Ratzeburg-Lauenburg of the Younger Line. In the same year, Eric IV, supported by his sons Eric (later ruling as Eric V) and John, forcefully captured the pawned areas without making any repayment, before Lübeck could take possession of them. Lübeck acquiesced for the time being. In 1420, Eric V attacked Prince-Elector Frederick I of Brandenburg and Lübeck allied with Hamburg in support of Brandenburg. Armies of both cities opened a second front and conquered Bergedorf, Riepenburg castle and the Esslingen river toll station (today's Zollenspieker Ferry). This forced Eric V to agree with Hamburg's burgomaster Hein Hoyer and Burgomaster Jordan Pleskow of Lübeck to the Treaty of Perleberg on 23 August 1420, which stipulated that all the pawned areas, which Eric IV, Eric V and John IV had violently taken in 1401, were to be irrevocably ceded to the cities of Hamburg and Lübeck, becoming their bi-urban condominium of Bergedorf (Beiderstädtischer Besitz). From the 14th century, Saxe-Lauenburg termed itself as Lower Saxony (). However, Saxony as a naming for the area comprising the older Duchy of Saxony in its borders before 1180 still prevailed. So, when the Holy Roman Empire established the Imperial Circles in 1500 as tax levying and army recruitment districts, the circle comprising Saxe-Lauenburg and all its neighbours became designated as Saxon Circle, while the Wettin-ruled Saxon electorate and duchies at that time formed the Upper Saxon Circle. The naming of Lower Saxony became more colloquial and the Saxon Circle was later renamed the Lower Saxon Circle. In 1659, Duke Julius Henry decreed in his general disposition (guidelines for his government) "to also esteem the woodlands as heart and dwell [of revenues] of the Principality of Lower Saxony." After the Reformation The people of Hadeln, represented by their estates of the realm, adopted the Lutheran Reformation in 1525 and Duke Magnus I confirmed Hadeln's Lutheran Church Order in 1526, establishing Hadeln's separate ecclesiastical body existing until 1885. Magnus did not promote the spreading of Lutheranism in the rest of his duchy. Lutheran preachers, most likely from the southerly adjacent Principality of Lunenburg (Lutheran since 1529), held the first Lutheran preaches; at the northern entrance of St. Mary Magdalene Church in Lauenburg upon Elbe, one is recalled for Saint John's Eve in 1531. Tacitly, the congregations appointed Lutheran preachers so that the visitations of