New Integrated Knowledge based approachs to the protection of cultural heritage from Earthquake-induced Risk

The Old City of Akko (Acre)
The Hospitaller Center
Conservation measures in 2003
OrdererOld Akko Development Company, Ltd.
AddressBlock: 18009, Lot: 2
Implemented by: Yotam Carmel
Orit Soffer
Vadim Zaytlin

The fortress is located in the northern part of the Old City, next to the city wall. It was the center of the Hospitaller Quarter in Crusader Akko and its construction as a fortified compound was carried out in stages.
The conservation measures in the fortress include accompanying the archaeological excavation and overseeing the development in the compound, documenting the condition of the remains and restoration activities, providing solutions to engineering problems in the structure, conservation of existing architectural elements and the restoration of architectural elements utilizing original techniques and materials.
The Hospitaller Order arrived in Akko during the first years of the Crusader occupation of the city, at the beginning of the 12th century CE. Construction of the fortress probably commenced in 1135 CE and the earliest evidence we have of its existence is from 1149 CE. It was described in 1169 CE as a fortified and impressive structure which only the Templar fortress can compare to. Akko fell to the Muslims in 1187 CE and its Christian residents fled only to return there in 1191 CE following the recapture of the city by Richard Lion-Heart, during the Third Crusade in the Land of Israel. The knights of the Hospitaller Order returned to their residence in Akko but the existing buildings were no longer adequate for their requirements (in this period Jerusalem remained under the control of the Muslims and the order lost its main stronghold there). Consequently, the new rulers of the kingdom granted the Hospitallers concessions to enlarge their center in northern Akko. At the end of the 12th century and in the beginning of the 13th century CE they added additional wings and stories to the original compound.
With the Muslim conquest of Akko in 1291 CE the Hospitaller compound was abandoned and remained desolate until the 18th century CE, when a new Moslem city was built in Akko on top of the remains of the Crusader city. The Crusader structures were filled with earth and sand and served as the foundations for the Ottoman buildings. The first evidence of the existence of Crusader buildings beneath the Ottoman structures was discovered in the 1940’s; however, it was only in the 1950’s and 60’s that the first archaeological excavations were conducted in which Halls 1-3, part of the Hall of Pillars (“Grand Munier”) and the Crusader dining hall (“crypt”) were exposed.
In 1990 cracks were discovered in the ceiling of the Hall of Pillars. Following this discovery archaeological soundings were commenced in the vicinity of the exercise courtyard of Akko Prison, which developed into the extensive excavations of the Crusader compound. The excavations were conducted by the Antiquities Authority, with funding provided by the Ministry of Tourism. As of 2003 most parts of the compound have been exposed: an open courtyard and the southern, eastern and northern wings. The western wing, which has not yet been exposed, lies beneath the Shadaliah compound – a Muslim religious compound belonging to the Sufi sect (Stern E. 2000. The Center of the Hospitaller Order in Akko. Qadmoniot 119: 4-12).
Conservation of the fortress requires different levels of treatment for the engineering problems. The Ottoman buildings that were constructed on top of it have caused severe static problems to the vaults and supporting pillars.
The original building materials (stone and bonding material) throughout the entire complex suffer from intense weathering stemming from chemical-mechanical reasons; a high level of salt as a result of its proximity to the sea; high humidity; weather damage (wind, rain, air pollution); mechanical tension, missing architectural elements (windows, pillars, arches, vaults –  these were probably destroyed during the Ottoman building phase and some were damaged in the current excavations) and the development of biological nuisances (vegetation, moss, and biological patinas) inside and on the stone walls as a result of a combination of high humidity, porous building materials and a lack of maintenance.
The conservation of the fortress began in the 1990’s at the same time as the archaeological excavations and the removal of the earthen fill from inside the Crusader buildings. The first conservation steps were focused on engineering stabilization in those parts of the fortress where structural problems had occurred.
The conservation measures undertaken at the site include the planning of engineering supports in the Hall of Pillars and in the southern and eastern roads, grouting and inserting anchors into the vaults, restoring architectural elements (openings, pillars, walls, missing stones) and conservation of the stone and plaster (stabilization, cleaning and replacing what is missing).
The current conservation intervention focused on the individual problems of each specific location while at the same time an attempt was made to maintain uniformity with the conservation steps that were carried out in the past.
The locations where work was conducted in 2003 appear in the table below:
Hall of Pillars (“Grand Munier”)
A - Vault I and P: Reinforcing and grouting.
B - Wall of the “Beautiful Hall”; replaced missing stone work, grouting, pointing up the joints and conserving the surface of the stone.
C - Pillar 16: continued the restoration of the upper part of the pillar and dressing the cornice stones.
Dining Room (“Crypt”)
D - Southern wall: restoration of the window.
E - Eastern wall: replaced missing stone work.
F - Western pillar: continued conservation work.
Hall 7
G - Preliminary stabilization and replacement of missing stone work in the wall between Halls 7 and 8.
The Street
H - Conservation of the Crusader plaster.
The continuation of the conservation measures at the site necessitates intervention in the parts of the compound that have still not been attended to, extensive treatment of the biological nuisances in all parts of the compound and the preparation of an overall maintenance program. 

To view the figures, click on the figure caption
1. Location of the fortress designated on an aerial photograph of Old Akko.

2. Plan of the Crusader level in the fortress.

3. Plan of the locations where conservation measures were undertaken in 2003.

4. Stone dressing implements used in the restoration of architectural elements.

5. Restoration of Pillar 10 in the Hall of Pillars: detail of the assembly of the stone seat for the cornice.

Additional Projects
 The Hospitaller Center - Conservation measures undertaken in the Dining Hall (the “Crypt”), 2003
 The Hospitaller Center - Conservation measures undertaken in Hall of Pillars (“Grand Munir”)
 The Hospitaller Center - Conservation work in Halls 7, 8, 2003
 The Hospitaller Center - Crusader plaster on the southern road, 2003
 Old Akko, Hamam al-Pasha - The implementation of urgent (“first aid”) conservation and restoration measures
 The Eastern Land Wall - Conservation of the sentry boxes
 Hamam al-Pasha - The Conservation of the Fountain
 The ‘Città di Roma’ International Conservation Center in Old 'Akko - The Conservation and Rehabilitation of the Building
 The Knights Hospitaller Compound in Old ʽAkko - Conservation Work in the Hall of Pillars

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