Das 1614-1634 erbaute Residenzschloß in Idstein

Successors of the Count Udalrich in Idstein became the Counts of Laurenburg. They were relatives of the archbishop of Mainz, who handed over to them the castle of Idstein, and who were required to expand the influence of the archbishopric of Mainz and to substantiate the power of the empire.

Since the middle of the 12th century, the Laurenburger changed their name after the castle NASSAU. During this time Idstein became part of Nassau and remained there until 1866.

When the counts of Nassau divided their properties in 1255 and the Lahn river became the borderline between two different territories, Idstein became the main castle and thus a center of power in the Taunus area and furtheron south of the Lahn river.

Around this center, that place developed, for which Count Adolf of Nassau obtained the freedom of a city by King Rudolf of Habsburg in 1287. Count Adolf himself was German King from 1292 - 1298 and was killed in action during the battle against Albrecht of Austria at Gollstein. In the ensuing two centuries there were four counts of Nassau whi became the archbishops of Mainz and therefore, once again, were among the most powerful in the empire. The first one was Count Gerlach, 1346 - 1371. He was succeeded by three counts from Idstein:

Adolf 1373 - 1390
Johann 1396 - 1419
Adolf 1461 - 1475.

During the tenure of the last count of Idstein on the archbishop chair in Mainz falls the Mainz Chapter Feud, 1461 - 1463 during which two archbishops of Mainz were fighting against each other: Adolf of Nassau and Dieter of Isenburg. The Feud ended with an agreement. However, Mainz and Idstein were weakend to an extent that they never again reached their earlier power and importance.

From this first powerful time of Idstein stems the tower, called the Hexenturm "Witch tower", the oldest maintained monument of Idstein. Assumedly, ist construction began, after counts of the Walram lineage divided their property in 1355 and thus had established the lineages Nassau-Idstein and Nassau-Weilburg. The older lineage of the house Nassau-Idstein existed until 1605, when Johann Ludwig II. died at childage.

Parallel to the development of the castle-borough to a town, progressed the spiritual (religous) organization. The oldest church was already built prior to the time Idstein obtained the freedom of a city. Part of the construction can be found in today's protestant church. At the beginning of the 14th century, Count Gerlach promoted the establishment of a spiritual center which finally resulted in the expansion of the rights of this church, the increase of ist income, and the foundation of the St. Martin chapter at Idstein. This first school in Idstein set the beginning of long, manifold school history, that established Idstein's name as "City of Schools".

Since the end of the 15th century Idstein had lost ist political expansion power and has not enlarged ist properties. To the contrary, Wiesbaden, which belonged to the Idstein Reign, was, from time to time, ruled separately, until it was again unified with Idstein in 1511.

A bright, political event however was upcoming yet, before in 1540 the reformation entered the Idstein area also and in ist consequences included the counts of Idstein in the political development within the empire. In 1502, Emperor Maximilian I. visited Idstein. To honor his imperial friend, Count Philipp I. directed in 1497 the erection of the archway-building and assumedly, the alteration of the old castle tower. The archway-building remained unchanged until the present, while the etchings of Dillich, Meissner and Merian portray the appearance of the castle tower. Today's design is based on an alteration of 1810.

Many of the historical buildings of old Idstein stem from the late 16th and early 17th century, which, by location, size, framework and ornaments are evidence of the wealth and the pride of the owners. This proves that, in spite of the loss of the political influence, the civil - city life was blooming and uprising until it extinguished during the difficult time of the 30 years war. But, at least, the buildings of the city survived the war and provide, until today, the evidence of the citizen's self-confidence.

The older Idstein lineage became extinct in 1605; the counts of Nassau-Weilburg became heirs their construction and organizational plans stagnated during the war and their sovereignty broke down totally when the political actions of the younger lineage of the counts of Nassau-Idstein, established in 1629, could not prevent the fate. The counts of Nassau lost their territories and had to escape. The counties were temporarily governed by imperial commissioners; Wiesbaden was temporarily transferred to Mainz. In 1646 Count Johannes returned from Strassburg and, prior to the conclusion of the peace of Westphalia, concentrated on the rehabilitation of this land. From the first phase of construction stem the "Heersche Haus" and the southern part of the castle.

After the partical demolition of the old castle, which no longer corresponded with the requirements of the time, the construction work started at the same location and continued until 1634. The architect was Jost Heer. The "Heer House", a magnificent construction, based on a Franconian lay-out, was built by Heinrich Heer. The known Idsteiner Painter, Ernst Toepfer, born in 1878, after whom the house is named, lived in this impressive building until he died in 1955.

The remodelling of the old wotm church falls in the years of the sovereignty of Count Johannes. The alteration and decoration show a unique monument of the desire for construction and representation of the sovereigns of this time in a residence of Nassau. Especially the mural and ceiling paintings, performed by painters of the "Rubens-School" assure ist importance for the history of art.

After the death of Count Johannes in 1677 Georg August Samuel became the sovereign to. He continued the rehabilitation and expansion programm of his father and has, through his actions, once again reiterated the former power and importance of Idstein, before the lineage finally became extinct in 1721.

Under the sovereignty of Georg August, who accepted the title as sovereign, Idstein was expanded beyond the old city walls.

The drainage of the Weiherwiese (pond meadow) - today route B 275 - and the "new home area" between the Weiherwiese and Borngasse had been planned and executed by Georg August to expand the city and to increase the economic structure and significance. Streetnet, type of construction and the lay-out of a second market-place are good indications of the regulating guidance. Also, the castle in Wiesbaden-Biebrich, where the residence was moved to, after several successions of the Walram lineage (1721 Idstein to Ottweiler; 1723 Saarbrücken to Ottweiler; 1728 Ottweiler to Usingen) was built under Georg August. Idstein's history as the residence of Nassau ended with his death.

During the reformation the Martin chapter was converted into a High School/Junior College; ist good reputation made it attractive to all walks of life. The school existed until 1817, when the High School/Junior College at Weilburg was declared to be the only High School/Junior College of Nassau.

1789 a teacher's Training-College was established in Idstein, which at first remained closely connected with the High School/Junior College. When it was finally abolished, the training-college gained significance. The reform of the school system in Nassau was supported by the college, the ideas and thoughts of Pestalozzi have been implemented in teacher training and the educational programs. The training-college existed until 1851. Closely related with the training of teachers was the institute of agriculture at the Gassenbach-Farm, which, under the guidance of Wilhelm Albrecht, ran a modelfarm and knowledge gained was conveyed to the country-man to improve the state culture and the agriculture basis. 1833 the institute was transferred to Wiesbaden.

Simultaneously with the new educational establishment, a century old tradition, the tannery trade came into being, the fine leather fabrication. The first leather factory was founded in 1810 (today "Hotel Felsenkeller"). This was the beginning of Idstein's industrialization, which, expecially during the period of promoterism and when the railroad was built, rapidly boomed; it ended during the inflation after World War I. Up to the present time however, the leather industry is well represented in Idstein. Evidence of this old trade is the only still maintained tannery house at the parking lot Löhergasse.

In relation of the history of civilization and politically, it has to be pointed out that, since the duchy of Nassau was organized from the various dynasties of Nassau in 1806, which, until 1866, when it became prussian, was a unified formation of states, the Nassau Union was concluded in Idstein in 1817, when the Lutheran and Reformed were unified in one church out of which the Nassau State Church was constituted. The old Martin Church, having been the city church and, lateron also the castle church, has been called Union Church since that time.

Until 1881 the castle accomodated the Nassau State Record Office and then served several other purposes, until, after having been utilized as a military hospital during World War II., it accomodated the newly established High School/Junior College in 1946. Over centuries, life in Idstein was determined by ist function as clerical and spiritual center of an area which, until the end of the middle age, also was of significance for the politics within the empire. The basis for the modern Idstein is of a different nature, it is to be found in the working environment, craft, treade an lately in the industry. After 1945 the structure of Idstein was changed basically. The immigration of expellees (each fourth citizen stems from the former German eastern areas and the Sudetes), the planned city expansions, the establishment of larger industrial firms, known world wide, the political reform of the area and consequently the expansion of the structural functions, and, last not least, ist central location in the traffic net, have changed the former Nassau Residence with a population of 4.500 in 1939 to a central place with a population of 22.500 which offers ist inhabitants not only living and job possibilities, but also meets manifold requirements and thus meets the necessities of life of the present time.