Eric II already involved his son Eric IV young in government affairs.[1] Eric IV succeeded his father in 1368 as Duke of Saxe-Ratzeburg-Lauenburg.
Neighbouring territories (Prince-Archbishopric of Bremen, Hamburg, and Schauenburg and Holstein-Kiel) had been at feud with the Saxon dukes Eric II and his cousin Albert V since 1363. In 1378 Prince-Archbishop Albert II reconciled with Eric IV, who had married Albert's niece Sophia. Eric IV and Albert II signed a peace, concluding to settle future disputes – especially on the Saxon exclave Land of Hadeln, neighbouring the prince-archbishopric – without using violence.[2]
Between 1392 and 1398 Eric IV carried out the constructions of the Stecknitz Canal, connecting via Elbe and Trave the North Sea with the Baltic Sea.[3] This was the first European canal crossing a drainage divide, and was especially important for trade with the entire Baltic Rim.
In 1400 Eric IV confirmed Hamburg's purchase of Ritzebüttel from his local vassals Lappe.[4] In 1394 Hamburg had conquered the fortress of Ritzebüttel in order to make it its stronghold to protect the estuary of the river Elbe.
In 1401 Eric IV inherited Saxe-Bergedorf-Mölln from his cousin of second degree Eric III. Eric IV reunited the two branch duchies into Saxe-Lauenburg and subsequently shared his reign in the reunited duchy with his sons Eric V and John. However, most of Saxe-Bergedorf-Mölln had been alienated, such as the Herrschaft of Mölln (sold to Lübeck in 1359 under a repurchase agreement) and the Herrschaft of Bergedorf, the Vierlande, half the Saxon Wood and Geesthacht, all of which Eric III had pawned to the city of Lübeck in 1370.[5]
Eric III Duke of Saxe-Ratzeburg-Lauenburg had further entitled Lübeck to take possession of these areas, once he had deceased, until his heirs would repay the credit and thus redeem them and simultaneously exercise their right to repurchase Mölln, requiring altogether a total sum of 26,000 Lübeck marks. Still in 1401 Eric IV, supported by his sons Eric V and John, forcefully captured the pawned areas without any repayment, before Lübeck could take possession of them. Lübeck acquiesced.[6] In 1407 Eric IV pawned the northern part of Hadeln to Hamburg, four years later the southern part to Bremen.[7] In 1411 Eric IV and his sons Eric V and John IV pawned their share in the Vogtei over the Bailiwick of Bederkesa and in the Bederkesa Castle [de] to the Senate of Bremen including all "they have in the jurisdictions in the Frisian Land of Wursten and in Lehe [de], which belongs to the afore-mentioned castle and Vogtei".[8] Their share in jurisdiction, Vogtei and castle had been acquired from the plague-stricken Knights of Bederkesa,[8] who had dropped into decline after 1349/1350.
Marriage and issue
On 8 April 1373 Eric IV married Sophia of Brunswick-Lüneburg (1358–28 May 1416), daughter of Magnus II, Duke of Brunswick-Lüneburg. and they had the following children:
^Cordula Bornefeld, "Die Herzöge von Sachsen-Lauenburg", in: Die Fürsten des Landes: Herzöge und Grafen von Schleswig, Holstein und Lauenburg [De slevigske hertuger; German], Carsten Porskrog Rasmussen (ed.) on behalf of the Gesellschaft für Schleswig-Holsteinische Geschichte, Neumünster: Wachholtz, 2008, pp. 373–389, here p. 377. ISBN978-3-529-02606-5
^Elke Freifrau von Boeselager, "Das Land Hadeln bis zum Beginn der frühen Neuzeit", In: Geschichte des Landes zwischen Elbe und Weser: 3 vols., Hans-Eckhard Dannenberg and Heinz-Joachim Schulze (eds.) on behalf of the Landschaftsverband der ehemaligen Herzogtümer Bremen und Verden, Stade: Landschaftsverband der ehem. Herzogtümer Bremen und Verden, 1995 and 2008, (Schriftenreihe des Landschaftsverbandes der ehem. Herzogtümer Bremen und Verden; No. 7), vol. II: Mittelalter (1995), pp. 321–388, here p. 343. ISBN978-3-9801919-8-2
^Cordula Bornefeld, "Die Herzöge von Sachsen-Lauenburg", in: Die Fürsten des Landes: Herzöge und Grafen von Schleswig, Holstein und Lauenburg [De slevigske hertuger; German], Carsten Porskrog Rasmussen (ed.) on behalf of the Gesellschaft für Schleswig-Holsteinische Geschichte, Neumünster: Wachholtz, 2008, pp. 373–389, here p. 377. ISBN978-3-529-02606-5
^Cordula Bornefeld, "Die Herzöge von Sachsen-Lauenburg", in: Die Fürsten des Landes: Herzöge und Grafen von Schleswig, Holstein und Lauenburg [De slevigske hertuger; German], Carsten Porskrog Rasmussen (ed.) on behalf of the Gesellschaft für Schleswig-Holsteinische Geschichte, Neumünster: Wachholtz, 2008, pp. 373–389, here pp. 377. ISBN978-3-529-02606-5
^Elisabeth Raiser, Städtische Territorialpolitik im Mittelalter: eine vergleichende Untersuchung ihrer verschiedenen Formen am Beispiel Lübecks und Zürichs, Lübeck and Hamburg: Matthiesen, 1969, (Historische Studien; 406), p. 90, simultaneously: Hamburg, Univ., Diss., 1969.
^Elisabeth Raiser, Städtische Territorialpolitik im Mittelalter: eine vergleichende Untersuchung ihrer verschiedenen Formen am Beispiel Lübecks und Zürichs, Lübeck and Hamburg: Matthiesen, 1969, (Historische Studien; 406), p. 137, simultaneously: Hamburg, Univ., Diss., 1969.
^Cordula Bornefeld, "Die Herzöge von Sachsen-Lauenburg", in: Die Fürsten des Landes: Herzöge und Grafen von Schleswig, Holstein und Lauenburg [De slevigske hertuger; German], Carsten Porskrog Rasmussen (ed.) on behalf of the Gesellschaft für Schleswig-Holsteinische Geschichte, Neumünster: Wachholtz, 2008, pp. 373–389, here p. 377. ISBN978-3-529-02606-5
^ abIn the Middle Low German original: „wes zee hebben an gherichte in Vreslande . . . unde an Lee, dat to deme vorscrevenen slote unde voghedie höret", here after Bernd Ulrich Hucker, „Die landgemeindliche Entwicklung in Landwürden, Kirchspiel Lehe und Kirchspiel Midlum im Mittelalter“ (first presented in 1972 as a lecture at a conference of the historical work study association of the northern Lower Saxon Landschaftsverbände held at Oldenburg in Oldenburg), in: Oldenburger Jahrbuch, vol. 72 (1972), pp. 1–22, here p. 13.
