Considering the effects of the Byzantine–Islamic transition: Umayyad glass tesserae and vessels from the qasr of Khirbet al-Mafjar (Jericho, Palestine)

The paper reports and discusses data obtained by archaeological and archaeometric studies of glass vessels and tesserae from the qasr of Khirbet al-Mafjar (near Jericho, Palestine). Archaeological contextualisation of the site and chrono-typological study of glass vessels were associated to EPMA and LA–ICP–MS analyses, performed to characterise the composition of the glassy matrix (major and minor components as well as trace elements). Analyses allowed achieving meaningful and intriguing results, which gain insights into the production and consumption of glass vessels and tesserae in the near East during the Umayyad period (seventh–eighth centuries). Within the analysed samples, both an Egyptian and a Levantine manufacture have been identified: such data provide evidence of a double supply of glass from Egypt and the Syro-Palestinian coast in the Umayyad period occurring not only in the glassware manufacture but also in the production of base glass intended to be used in the manufacture of mosaic tesserae. Thus, the achieved results represent the first material evidence of a non-exclusive gathering of glass tesserae from Byzantium and the Byzantines in the manufacture of early Islamic mosaics.

On the other hand, authors are not able to access the forthcoming paper by Verità et al. Scientific investigation of glass tesserae from the 8 th century AD archaeological site of Qusayr Amra (Jordan) as the book "The colours of the Prince" has not been published yet by ISCR.
2 113-129 (were 90-105): authors do not mention cullets, but tesserae and vessel fragments. The discussion concerns a consumption site and no evidence for a secondary workshop has been discovered. It is not possible to know if the tesserae originally belonged to a wall or floor decoration because no decoration is preserved. The authors are aware that the chronology of the materials found in a layer of the second phase could be a controversial issue but this does not necessarily imply they were used and produced before. The chrono-typological and archaeometric study reported in the following parts of the paper add data to aid the interpretation.

Materials and methods
131-171 (were 116-134): in the authors' opinion, the aim of the Introduction of the paper is to contextualize the study and introduce the material selection. We are aware that the Materials section is, generally, a list of objects and samples whereas, in this case, it represent a chrono-typological study of the analysed materials. For this reason, we prefer to keep the section of material description separated from the Introduction and a re-naming of sections was proposed by introducing Section 2. Chrono-typology of glass findings and naming the following section 3. Experimental Typologies and comparisons were revised according to reviewer's comments and suggested references.
Tab. 2a,b: authors would prefer to keep tables in the text.
A6 tessera can be better defined as "weak turquoise", as authors agree that "pale blue" could be confusing.
A15 is not a cobalt-coloured blue tessera. Authors believe it could be better described as "weak turquoise" rather than "pale blue" so as to avoid misunderstanding.
168 (was 141): there are no indication about Am12 and Am14 being gold leaf tesserae. Only Am/Au11 is a gold leaf one, that lost cartellina and shows traces of the gold leaf on one side.

184-205
(were 158 and 160): standard deviation and accuracy are now provided. Standard materials used as references are indicated in the text, in the Experimental section. Text was changed and requested information added. Ten measurements were performed to test homogeneity, because we are also analysing opaque coloured tesserae. As inserted in the revised version (lines 94-96), an in-depth characterisation of colourants and opacifiers used in the secondary manufacture of the tesserae is currently being carried out, by means of a multi-analytical approach (VIS-RS, OM, SEM-EDS, micro-Raman), and not reported here.

Results
Tab.2 and Tab.3 have been improved according to the requests.

216-218
(were 185-188): in the Egypt I opaque tesserae, FeO is always correlated to TiO2 (see the scatter plot reported below) and it was not subtracted; concerning the Levantine tesserae, the only samples not displaying a correlation between FeO and TiO2 are Am12 (translucent weak brown) and A15 (translucent weak turquoise). However, following a homogeneity criteria, we propose to maintain the choice of non-subtracting FeO, after having checked that the effect on data and discussion for the two samples is negligible. (were 192-194): we agree that, in the case of A15 tessera, the higher MgO, K2O, and P2O5 contents could also indicate a recycling process and, consequently, we took this interpretation into account. Authors would prefer to keep this sentence in the original position, because it is linked to the previous one.

223-226
Were [195][196][197]: these lines have been deleted as requested. (were 199-236): The opinion of the authors is that the results concerning the glassy matrices of vessels and tesserae need to be separated because different compositional categories were identified (Egypt I, Apollonia-type and Bet Eli'ezer-type for the tesserae; Egypt II, Apollonia-type and Bet Eli'ezer-type for the vessels). The reason for discussing trace element data before major oxides primarily stems from the fact that trace element patterns and REE distributions allow to precisely define the type of sand employed in the manufacture of the base glass, providing a precise indication on the provenance of the raw materials. This approach in discussing data has recently been proposed by Phelps at al. 2016 and authors believe it could be incisive also in this case.

Discussion
Authors are aware that the discussion of the achieved data is quite complicated. Instead of rewriting the whole section, we would like to propose some changes to the original text according to the reviewer's comment. Figures were changed and improved. 317: authors accept the reviewer's comment and suggest to remove this topic.
Introduction was improved and the still open questions discussed more thoroughly.
VIS-RS data were removed. Actually, the entire part on colourants and opacifiers was removed since preliminary data were improperly presented. Authors agree with the reviewer that data on colour and opacity should be discussed in depth. Therefore, an in-depth characterisation of colourants and opacifiers used in the secondary manufacture of the tesserae is currently being carried out, by means of a multi-analytical approach (VIS-RS, OM, SEM-EDS, micro-Raman), and is not reported here (see revised version lines 94-96).
Figures were improved as suggested and references added when requested.
In paragraph 4.1, the discussion on natron shortage was removed since this issue requires further indepth analysis.

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The present paper reports and discusses base glass compositional data about naturally coloured glass 93 vessels and tesserae from the qasr of Khirbet al-Mafjar. An in-depth characterisation of colourants 94 and opacifiers used in the secondary manufacture of the tesserae is currently being carried out, by 95 means of a multi-analytical approach, not reported here.

96
Also known as Hisham's Palace, by the name of the Umayyad caliph who ordered its construction in 97 the first half of the 8 th century, the qasr of Khirbet al-Mafjar is an amazing example of Desert Castles, 98 winter residences of the Islamic caliphs. Located in the plain of Jericho (3.5 km north of the city -99 Fig. 1a), it is considered to be one of the most significant archaeological evidence of the early Islamic drawing of the building has been provided ( Fig.1b), with a wider comprehension of the phasing.

116
According to archaeological evidence, it can now be stated that the Original Residence was 117 contemporaneous with a Grape Press for wine production, recently discovered and early Umayyad in 118 date. Moreover, during the last research seasons, it also emerged that this phase was probably 119 connected to a wider building, identified by remote sensing investigations that highlighted several 120 differently orientated hidden structures, in a middle area between the palatial complex and the 121 northern building. The central area of the new building was never excavated and it is probably 122 connected to an earlier period of occupation, dating back to the Late Roman (end of the 7 th century) 123 or early Umayyad (7 th -8 th century), possibly belonging to the period of Sulayman ibn Abd al-Malik 124 (715-717 AD). The mosaic tesserae and the other glass fragments belong to a second phase, dated to 125 the Hisham's caliphate (724-743 AD), and they were connected to the court of the Northern Building, 126 soon after the abandon of the large agricultural estate. Moreover, the Northern Building was 127 abandoned after having been damaged by the earthquake, and, consequently, the findings can be 128 confidently ascribed to the period between 724-748\9 AD (Whitcomb 2013  Among the tesserae, a set of 16 coloured samples (11 opaque and 5 translucent) was selected ( Table  164 1.b). The opaque sub-group comprises 4 tesserae in various shades of green (Vsr4, V5, Vc8, Vc9), 3 165 in different tones of weak turquoise (A6, A7, A7 bis), 1 of a deep red glass (R1), 1 of a greenish-166 yellow glass (G/V3), 1 of a yellow glass (G2), and 1 of a greyish pale blue glass (Ga10). The 167 transparent sub-group is formed by: 2 tesserae of brown glass (Am14, Am12), 1 of brown glass with 168 golden leaf (Am/Au11), 1 of a weak turquoise glass (A15) and 1 of greenish-yellow glass (G/V13). 169 170

Experimental 171
All samples were preliminary cleaned by using demineralized water and dentist tools, softly scraping 172 the surfaces to remove remains of soil and dirt. 173 An Olympus S761 stereomicroscope (magnification up to 45x) associated with an Olympus Soft 174 Imaging Solutions GMBH model SC100 camera was used for a preliminary morphological 175 observations and documentation.

176
A NCS (Natural Colour System) chart was used to provide a preliminary objective definition of the 177 colour of the tesserae.

351
Whilst the production and consumption of Egypt II glass has been frequently documented in the 8 th 352 century Vc8, Am/Au11, G/V13, Am14) have been manufactured by using sands low in the heavy accessory 367 minerals, with small contents of iron oxide, titanium oxide and zirconium, and showing a greater REE 368 depletion (Fig. 4a-d). In addition, the relatively high alumina suggests the use of a mature sand, and 369 the positive correlation between high lime and high strontium indicates a coastal sand containing 370 shells (Fig. 5, 8)  Concerning the vessels, patterns elucidated on the basis of LA-ICP-MS data markedly distinguish 388 KH04 and KH06 samples from the Egyptian set ( Fig. 4a,b) Eli'ezer-type (Levantine II) group ( Fig. 4 and 7); this hypothesis is further enhanced by the chrono-403 typological data, since this fragment of a flat bottom, probably belonged to a globular bottle, is similar 404 to some types documented in the catalogue of the glass findings from Al-Hadir (northern Syria) (Foy 405 2012), dated from the 8 th century AD onwards, therefore of a slightly later time.