Patrícia A.R. Monteiro, The ingenious art of deception: decorative techniques involving lime plaster mixtures in the grotto of the Ducal Palace in Vila Viçosa, e-conservation Journal 4, 2015
Available online 14 November 2015
The ingenious art of deception: decorative techniques involving lime plaster mixtures in the grotto of the Ducal Palace in Vila Viçosa
Patrícia A.R. Monteiro
The Alentejo region still preserves a considerable artistic heritage in which the use of lime has always been a priority item. In fact, its use throughout the ages is the best testimony of ancient decorative techniques, deeply rooted in the Iberian Peninsula. The great versatility of lime when combined with different aggregates (sand, pigments, marble dust) allowed the development of different techniques that come down to the present day, from mural paintings, sgraffitti, whitewashed facades, and also ornamental mortars made with mixtures of lime and sand, gypsum or lime and gypsum (stucco). The theme of the mortars (both in lime and sand, or lime and gypsum) has been explored mainly from a technical point of view by several professionals working in architecture or engineering. We think it is crucial to give also the perspective of the art historian, in order to characterize all the aspects concerning to this issue, as we are dealing with a heritage in imminent danger of complete disappearance.
This topic has been covered in ancient Art treatises by both national and foreign authors. From those, we wish to emphasize the Arte de hacer el stucco jaspeado  and the Pintura simples , just to number a few. The first teaches the construction method of a masonry altarpiece before being plastered and painted while the second is of vital importance concerning decorative techniques, especially those involving the use of mortars. Currently, we can find works addressing the artistic production methods through plaster and lime [3, 4], although there are still some gaps that remain, namely the one of altarpieces.
In Portugal, the studies on traditional mortars focus, first of all, on their function and behaviour while lining of historic buildings [5, 6]. Only in a lesser extent, mortars have been studied as an art object per se, as in the case of the decorations of the Algarve’s popular architecture .
The Alentejo region was also the subject of study by researchers from different areas of knowledge that not only rejected the concept of the white limewash domination , but also distinguished this same region as a perfect repository of decorative techniques that enriched the architecture itself [9, 10]. Not only mural paintings, but also the sgraffitos can definitely be included within this logic. The diversity of the ornamental motifs reproduced by the sgraffito technique, applied both in facades and interiors, was carefully analysed from a technical and stylistic point of view by Sofia Salema .
The first systematic survey of decorative mortars was performed only in 2009 in an inventory of all the ornamental elements remarkable at the level of facades in the districts of Évora and Portalegre . This inventory refers to both sgraffito and stucco, missing to clarify some concepts, given the specificity of each technique. Studies concerning ornamental works at vaults or masonry altarpieces are even scarcer. In this matter, one of the works to be highlighted is the analytical study of the Gaspar Fragoso’s altarpiece in the Saint Francis convent in Portalegre .
The extreme rarity of such artworks in Portugal requires an urgent comparison with similar cases outside the country. Good examples can be found in Italy, or in Catalonia where the production of stucco altars dates back to the medieval period . Also we must mention the case of England where this tradition, still today, is kept .
Portuguese studies of Art History have focused almost exclusively on lime, gypsum or lime gypsum plasters and its evolution , highlighting the Oporto region as a centre of production [17, 18], especially for the period of the second half of the 18th century .
All these studies from different areas of knowledge will be the basis of a new multidisciplinary line of historical and artistic research around the so-called “lime arts”.
2. Different categories of ornamental artworks
The tradition of ornamental lime-based mixtures is very strong in Alentejo. Their presence can be tracked to several areas inside and outside of buildings, both religious and civil, most often associated with mural paintings:
a) Altarpieces. There is still a considerable number of altarpieces, datable from the 16th till the 19th centuries, built with lime and sand mortars over a brick structure. These artworks represent, to this day, a double simulation: on the one hand the modelled mortars reproduce architectural or sculptural elements; on the other hand, the polychromatic coatings simulate richer materials (marble, golden leaf) (Figure 1).
b) Vaults and triumphal arches. In most cases, the high relief ornaments modelled in lime, gypsum or lime and gypsum plasters can be seen at the cornices level or at the vaults. These motifs, framing mural paintings, were then also painted or gilded (Figures 2 and 3).
c) Decorative elements in façades and gardens. Finally, decorative elements present at the exterior of the building, as part of the architecture (whether civil or religious), with very diverse decorative and conceptual solutions.
One of the situations in which ornamental lime, gypsum, or lime and gypsum plasters found greater expression was as being part of the equipment of private gardens of noble houses or palaces. The casa de fresco at Sanches de Baena’s house (Vila Viçosa) is one of the best examples of this art applied to the gardens. This space features a decorative program typical of the Mannerist style, combining mural paintings, plasterworks and lime-based mixtures inlaid with shelves and small pieces of porcelain .
Left to right:
Figure 1. Altarpiece of the Gaspar Fragoso’s chapel. Church of Saint Francis. Portalegre, 1571.
Figure 2. Vault in Saint Lawrence’s chapel (detail). Évora’s cathedral. 17th century (first half).
Figure 3. Vault of the chapel in the Évoras’ University. 18th century.
3. Main topics of research
The awareness of the artistic richness of decorative motifs made in lime plaster mixtures and their appalling state of degradation let us to outline several points that must be taken under consideration when studying this issue:
a) Bibliographic and documentary survey of ornamental works in lime-plaster mixtures with polychrome coatings;
b) Clarification of the terminology used;
c) Characterization of all the stylistic ornaments;
d) Technical study of the mixtures constituent materials especially in those cases considered as the most representative of each category. This analysis would be carried out within the scope of PRIM'ART project with the collaboration of the scientific team;
e) Differentiation of lime-plaster mortars from those who have other components;
f) Identification of common features (stylistic, material and conceptual) between the modelled decorative mortars and the mural painting (the notion of the artwork as a whole);
g) Comparison with similar works of art in other parts of the country;
h) Dissemination of conclusions (publication of articles, participation in conferences and/or workshops, etc.).
4. A case study: the “Amazons Garden” in the Ducal Palace of Vila Viçosa
One of the most interesting (and unknown) works of art made only with lime-based mixtures is located in Vila Viçosa, within the so-called grotto of the “Amazons’ Garden” belonging to the Ducal Palace. This precious testimony of the Mannerist period regained visibility, after being saved from deterioration by the conservation works undertaken by the company Nova Conservação (2014).
Through a rusticated arch there is access to the interior area of the grotto, as in the good way of Italian Mannerism. The interior is covered by a vault with mural paintings and an oculus at the centre. The back wall is dominated by two statues of great proportions of manly caryatids (Figure 4), depicted with a highly realistic sense, flanking one fountain. A third figure, of feminine features, seems to emerge from the source, bridging the other two.
Analyses performed by Hercules laboratory (University of Évora) on several samples showed that these three figures were sculptured in lime-based mixtures. Their level of refinement is notorious, especially in what concerns the anatomical details and drapery (as can be seen on the female figure) (Figure 5).
As a link between the three figures we can see luxurious garlands of fruits sprouting from the baskets that each one of the figures carries on their heads. All these elements are references to the abundance and richness of nature itself, with a strong connection to the presence of water, to which the caves location cannot be unrelated.
The mural paintings, covering the entire vault, assume the role of element of connection of the whole interior space, as well as with the nature surrounding the cave (Figure 6). The trees branches, depicted in the vault, stretch out like authentic vault ribs, amongst which numerous birds can be distinguished like a parrot, located in the axis of the composition, a signal of exoticism and wealth of nature.
Left to right:
Figure 4. Caryatid (detail). Fountain of the cave in the Amazon’s Garden. Vila Viçosa. 17th century. Photo by Milene Gil.
Figure 5. Feminin figure (detail). Fountain of the cave in the Amazon’s Garden. Vila Viçosa. 17th century. Photo by Milene Gil.
Figure 6. Mural paintings at the vault of the cave. Vila Viçosa. 17th century. Photo by Milene Gil.
In Portugal, there are not many examples of 17th century artificial caves built in gardens, especially with the greatness of that in the “Amazons’ Garden”. Its unique style is echoed in similar constructions built in Italy around the 16th century. We recall the example of Bernardo Buontalenti’s cave, (initiated by Vasari) near the Pitti Palace (Florence), built between 1583 and 1593 for Francis I of Medici. This is perhaps the most famous example of this type of constructions in the Tuscan Mannerism. Since then, it has influenced the architecture of gardens.
As in the case of Vila Viçosa, the cave combines architecture, with the mass work, the inlaid works, sculpture (there are copies of Michelangelo sculptures) and also mural paintings, created by painter Bernardino Poccetti (1542-1612).
The murals create a sense of continuity between lime plaster works, architecture and the surrounding landscape, reproducing it, and also creating an illusion of depth and infinity, as if there were no architectural barriers.
From a strictly symbolical point of view, artificial caves have a direct connection with the vast, terrible and unreal universe of the underworld. The decorative motifs of grottesche also share the same symbolic meaning. The artificial caves as elements linked to the fantastic had a very strong presence, especially in the Mannerism. Then, with the Baroque style, these caves acquired another kind of functions, more related with leisure especially with the evolution with the art of gardens in France and later in Spain (Gardens of the Royal Palace of La Granja de San Ildefonso).
5. Preliminary findings
The subject of decorative artwork constructed from mixtures of lime and sand is still largely to study. Entering the broad topic of "lime arts" this issue becomes far more complex and, therefore, a multidisciplinary approach will be required.
These artistic solutions reflect not only a strategic management of the material resources. In some cases, they feature a classical inspiration in Italian models, even in the interior regions of Portugal, showing the updated culture of noble patrons who ordered these artworks.
 R. Pasqual Diez, Arte de hacer el estuco jaspeado, ó de imitar los jaspes á poca costa, y con la mayor propriedad, Imprenta Real, Madrid, 1785
 L. Telles, Pintura Simples, A decoração na construção Civil, tomo I, Typografia do Commercio, Lisboa, 1898
 I. Gárate Rojas, Arte de los yesos. Yeserías y estucos, Editorial Munilla–Lería, Madrid, 1999
 I. Gárate Rojas, Artes de la cal, Instituto Español de Arquitectura, Universidad de Alcalá, Editorial Munilla-Lería, Madrid, 2002
 R. Veiga, As argamassas na conservação, Actas das 1ªs Jornadas de Engenharia Civil da Universidade de Aveiro, Avaliação e Reabilitação das Construções existentes, Aveiro, 26 de Novembro de 2003, COM 103, LNEC, Lisboa, 2003
 R. Veiga, Os revestimentos antigos e a identidade dos edifícios, Arquitectura Ibérica. Reabilitação 12, 2006
 M. Santos, Argamassas e Revestimentos, Materiais, sistemas e técnicas de construção tradicional: Contributo para o estudo da arquitectura vernácula da região oriental da Serra do Caldeirão, CCDRAlg/ Edições Afrontamento, 2008
 M. G. Casal, A Conservação e Restauro da pintura mural nas fachadas alentejanas: estudo científico dos materiais e tecnologias antigas da cor, PhD thesis, Faculty of Sciences and Technology, New Universidade of Lisbon, 2009
 J. M. A. P. da Costa, Estudos Cromáticos nas Intervenções de Conservação em Centros Históricos, Bases para a sua aplicação à realidade portuguesa, PhD thesis, University of Évora, Évora, 1999
 J. M. A. P. da Costa, M. Tavares, I. Mendonça, Fingidos de madeira e de pedra, Breve historial técnicas de execução de restauro e de conservação, CENFIC, Lisboa, 1998
 S. S. Guilherme, O Corpus do Esgrafito no Alentejo e a sua Conservação uma Leitura sobre o Ornamento na Arquitectura, PhD thesis, Faculty of Architecture, Technical University of Lisbon, 2012
 M. Braga, A. Charrua, Argamassas decorativas nos distritos de Évora e de Portalegre, no Alentejo, A Cidade de Évora: Boletim de Cultura da Câmara Municipal, 2.ª série, n.º 8, Câmara Municipal de Évora, Évora, 2009, pp. 501-571
 P. Monteiro, Polychrome coatings on a lime plaster altarpiece (1571): the Gaspar Fragoso chapel in Portalegre, in: K. Seymour (ed.), Proceedings of the ICOM-CC Interim Meeting: Polychrome Sculpture: Decorative Practice and Artistic Tradition (Working Group Sculpture, Polychromy, and Architectural Decoration), Tomar, 28 May 2013
 W. Cook, A Stucco Altar Frontal from Betesa, Speculum, A Journal of Mediaeval Studies, vol. XXXV, n.º 3, Cambridge, Massachusetts, July 1960, pp. 394-400
 T. Proudfoot, Decorative Lime Plaster, The Building Conservation Directory 2001, http://www.buildingconservation.com/articles/limeplast/limeplast.htm (accessed 28th march 2013)
 T. Freire, A. Santos Silva, M. R. Veiga, J. Brito, Characterization of Portuguese Historical Gypsum Mortars: a Comparison between Two Case Studies, Materials Science Forum, vols. 636-637, Switzerland Trans Tech Publications, 2010, pp. 1258-1265
 F. de Vasconcelos, Os Estuques do Porto, (col. Porto Património), Porto, Câmara Municipal, 1997
 E. M. da Silva, Revestimentos decorativos tradicionais de cal e estuque em Portugal, Escola das Artes, UCP, Porto, 2008, pp. 63-84
 I. M. G. Mendonça, Estuques Decorativos. A evolução das formas (séculos XVI a XIX), (col. Arte nas Igrejas de Lisboa, Patriarcado de Lisboa), Nova Terra, Lisboa, Principia, 2009
 M. Gil, V. Serrão, A. Santos Silva, J. Mirão, S. Valadas, R. Martins, A. Candeias, A Casa de fresco dos Sanches de Baena Elementos de estudo para o seu conhecimento, Callipole, Revista de Cultura 19, Câmara Municipal de Vila Viçosa, 2011
Faculty of Letters, University of Lisbon