Franconia. When Franconia fragmented in the early 13th century with the fall of the Hohenstaufen, Nassau emerged as an independent state as part of the Holy Roman Empire. Count Dudo-Henry of Laurenburg (ca. 1060 – ca. 1123) (; ) is considered the founder of the House of Nassau. Dudo was a son of Rupert (German: Ruprecht), the Archbishop of Mainz's Vogt in Siegerland. Dudo was himself lord or Vogt of Lipporn and Miehlen and owned large parts of the lands of Lipporn/Laurenburg. There are more persons known who, as owners of the lands of Lipporn/Laurenburg (and thus the predecessors of Dudo), probably also were his ancestors. The first is a certain Drutwin mentioned in 881 as a landowner in Prüm, and who is the oldest known possible ancestor of the House of Nassau. Dudo is mentioned as Tuto de Lurinburg between 1093 and 1117. Dudo built the castle of Laurenburg on the Lahn a few kilometers upriver from Nassau around 1090 as the seat of his lordship. He is first mentioned in a document in the purported founding-charter of Maria Laach Abbey in 1093 (although many historians consider the document to be fabricated). In 1159, Nassau Castle became the ruling seat, and the house is now named after this castle. In a charter dated 1134 (after his death) he is mentioned as Count of Laurenburg. In 1117, Dudo donated land to Schaffhausen Abbey for construction of a monastery in Lipporn. Around 1117, Dudo, Count of Laurenburg founded at Lipporn a Benedictine priory dedicated and named for Saint Florin of Koblenz, and dependent on the Benedictine All Saints Abbey in Schaffhausen. About 1126, his son, Rupert I, Count of Laurenburg, the Vogt of Lipporn, established it as a separate and independent abbey. The Romanesque buildings were constructed between 1126 and 1145, presumably with a three-nave basilica. The Abbey included both a monastery for monks and a small, separate one for nuns. In 1122, Dudo received the castle of Idstein in the Taunus as a fief under the Archbishopric of Mainz. This was part of the inheritance of Count Udalrich of Idstein-Eppstein. He also received the Vogtship of the richly endowed Benedictine Bleidenstadt Abbey (in present-day Taunusstein). The Counts of Laurenburg and Nassau expanded their authority under the brothers Robert (Ruprecht) I (1123–1154) and Arnold I of Laurenburg (1123–1148). Robert was the first person to call himself Count of Nassau, but the