The ground plan of Ronneburg reveals the rectangular core castle with its robust defensive wall. Together with the keep and the hall building, it is the oldest part of the castle dating from the second quarter of the 14th century. The extensive
outer bailey located to the south and east of the complex is a product of a later construction phase, spanning from 1538 to 1550. features a round ground plan with a diameter slightly exceeding eight meters. Its masonry, which is consistent up to the helmet, is believed to belong to the earliest construction phase. In the thinner masonry of the spacious hall on the fourth floor, the remains of a staircase embedded in the wall indicate its connection to the Renaissance-era helmet. The original entrance can be observed on the courtyard side on the third floor, situated at a height of about ten meters, as a pointed arched gate. The two floors below served as dungeons and were only accessible from above via a fear hole in the vault. The current windows were installed in 1581, requiring the wall to be broken through for their installation when it was intended to use these floors for residential purposes as well. In the 15th century, a new lateral access had already been created through an attached stair tower with a spiral staircase. Consequently, the 57-step spiral staircase within the keep only commences on the third floor and starts above a three-armed arch, likely because the original hole to the dungeon was not yet covered. The castle's distinctive Renaissance helmet, built between 1576 and 1581, was designed by master builder Joris Robin from
Ypres. Above the closed fifth floor, there is a gallery at a height of 25 meters with a
balustrade. The gallery is interrupted in the four main directions by a porch with small
gables through which it passes. Today, the two top floors are accessible via a wooden staircase. The dome above, made of ashlars, ends in a lantern. The Renaissance helmet of the Ronneburg keep is inspired by Italian cupola lanterns of the time, making it one of the most remarkable examples of Renaissance architecture in Hesse. The building houses a vaulted cellar, as well as larger living and courtrooms. It also contains a castle kitchen, which, however, was only installed during the Renaissance. In the past, the first floor featured a larger hall, which was later converted into a smaller hall with a kitchen. Half-timbered walls from the 15th century are still preserved on the middle floor. The upper floor had to be extensively rebuilt after the fire damage of 1621, so medieval elements are present only in the stone architectural components.
Castle chapel in the hall building Burg_Ronneburg_Kapelle_01.JPG|View of today's castle chapel on the upper floor of the hall building Burg_Ronneburg_Kapellenerker_2016.jpg|Detailed view of the chapel bay window Burg_Ronneburg_Kapellenerker_Innenansicht_2016.jpg|Inside view
Bakehouse Directly north of the hall building, in the corner between it and the old building, one can find the bakehouse. It has an impressive Renaissance gable on the exterior and dates to the 16th century. The
shell tower of the
late medieval Zwinger, which is directly adjacent to the outer corner, was extended to serve as a stair tower during the building's expansion.
Old building The Old Building occupies the space between the bay window of the New Bower to the east, the Hall Building, and the Bakehouse. The core of the building likely dates back to the 15th century. A portal on the courtyard side displays the date 1572. On the courtyard side, there are only three Renaissance windows, which were likely added at a later date. On the field side, with presumably older masonry, one can see a covered
embrasure from the mid-16th century, as well as a bricked-up light niche for a privy. The stately four-story building is 32.5 meters long and is just under nine meters wide. The courtyard-side
facade is divided by two high
oriels, one of which is a stander bay. On the left oriel, the blind
tracery on the two main floors and the coats of arms of the builders in the basement are conspicuous. On the right oriel, there are mirrored ashlars carefully decorated with a checkerboard pattern. They represent an outstanding example of Renaissance stonemasonry. Due to the fire of 1621, the top floor of the oriel, which today bears a sundial, is not original. Between the two oriels is the portal with the coat of arms of Ysenburg and von Gleichen, and next to it is the foundation stone with an inscription from 1573. The use of the individual floors is largely known from inventories: Count Heinrich's apartment was on the second floor and that of his wife and other relatives was on the second floor. Further living quarters were located on the third floor, which, however, has not been preserved in its original form due to the fire of 1621. Each floor had a privy at the transition to the Old Building. Each apartment consisted of a heated chamber and a sleeping chamber.
Interior views of the new bower Burg_Ronneburg_Mittleres_Herrengemach.jpg|Middle men's room on the first floor of the new bower Burg_Ronneburg_Neuer_Wohnbau_Erkergewoelbe_2_OG.jpg|Painted bay window vault on the 2nd floor Burg_Ronneburg_Wandinschrift_Neue_Kemenate_2016.jpg|Wall inscription
Zinzendorf Building (Fourth Gate House) At the Zinzendorf Building and the integrated innermost gatehouse, one can find various building eras of the castle. The outer archway from 1570 is supported by corner ashlars dating back to the 14th century. The passage is covered by a groined vault, which still displays remnants of Renaissance paintings. The inner archway leading to the castle courtyard is dated 1541, but it also features late medieval side walls, and the imposts may be among the oldest components of the castle. The Zinzendorf Building as it stands today was built in 1570 on the site of an older gatehouse, but it did not acquire its name until the 20th century. The building has a richly decorated oriel with blind tracery on the courtyard side, similar examples of which can be found in
Büdingen. The tracery of the window
parapet features the coat of arms of Count Heinrich von Ysenburg-Ronneburg and his first wife, Maria von Rappoltstein. On the adjacent staircase building, there's a foundation stone inscribed with the date "1570." The upper floor of the building above the gatehouse is entirely occupied by a hall. Since the 18th century, it served as a New Church for the resident religious community, named after
Nikolaus Ludwig von Zinzendorf as the Zinzendorfsaal. Originally, it was likely a larger living room dating back to the construction period of 1570. This hall features a rectangular Gothic vaulted bay window with ribbed vaulting on both the courtyard and exterior sides. To the southwest of the gate, the passage is flanked by a sturdy round tower. During the construction of the gate, a portion of the tower's masonry was removed, indicating that the tower is older than the current gateway and was adapted to it when the gate was reconstructed. In the 16th century, when the gatehouse to the north was converted into the well house, the guardroom was relocated to the first floor of this tower. Access to the well room is through the gate passage. The upper layers of the 96-meter-deep well are made of ashlars, and pincer holes and stonemason's marks are visible. The water surface is located at a depth of 84 meters, although the well originally had a depth of 125 meters.
Kennel In the late 14th or early 15th century, the hall building was enclosed by a bailey on its south and west sides. This bailey originally featured three semicircular shell towers. The northern tower was later heightened to serve as a stair tower for the bakehouse. The original third gatehouse was likely built around the same time as the kennel.
Forecastle The extensive outer bailey, situated in front of the core castle to the east and south, was built during the period when Ronneburg served as a residence, between 1538 and 1555. The northern part of the outer bailey was designed for defense and represents the primary attack side. This section features a high rubble stone wall with well-preserved battlements, including alternating covered and open embrasures, allowing defenders to engage enemies at the base of the wall. Notable architectural elements in this area include a pointed triangular bay near the gate, a pointed arched
sally port dating back to 1540 to the right of the cyngel, an aborter bay, and the later connection of the outer castle to the core castle. Visitors can explore these features by walking along a footpath around the castle.
Marstall The elongated Marstall, due to its size and location, resembles the main building of the outer castle. Two pointed-arched portals with inscriptions from 1549 and 1551 indicate the building's original construction period. However, the original upper floor was removed after 1838, when it was sold for demolition, and was only added back in 1964. Therefore, a historical impression of the building's structure can only be obtained on the first floor, where some plaster remnants are still preserved. Today, the Marstall houses the castle restaurant.
Band house The band house is situated in the center of the outer castle. It currently has only one floor but features a larger vaulted cellar. This building originally served as a wine storehouse. The foundation stone was laid by Barbara von Wertheim in 1554, and another stone at the neck of the cellar bears the date "1555." The original upper floor was destroyed in the fire of 1621, reconstructed in 1654, and eventually sold for demolition in 1870. The relatively flat roof that exists today was added in 1905. A monument located next to the building commemorates Peter Nieß, who made significant contributions to the research and preservation of the Ronneburg. The "Witches' Tower" was so named due to the tower stump of the high fortification of the outer castle, adjoining the Marstall to the southwest. In 1599, a woman accused of witchcraft was imprisoned there. Dates on an ogival portal in the basement and an embrasure on the outside indicate the tower's construction dates of 1550 and 1549, respectively. The prison was located only in the basement of the semicircular tower. At the top, it features a weir platform, which provides a good view of the actual height of the outer castle wall and the different types of embrasures. A round tower was built between 1546 and 1549 to protect the southwest corner of the outer castle. A pointed-arched portal dates back to 1548, and the adjoining section of the wall (the west wall of the outer bailey) was completed in 1549. The foundation stone from 1546 was later placed in the upper floor and bears the inscription,
"Do disz Mauer angefangen war, Graf Jorg den ersten Stein legt dar, des Augusts achtzehnten behalt, funffzehen hundert sechs vitzih zalt - 1546" (This wall was begun, Count Jorg laid the first stone, August's eighteenth kept, counting fifteen hundred six and twenty - 1546). The spiral staircase on the outside of the tower was added as late as 1905, using the reused steps from a staircase in the bakehouse. == Current use ==