From Greece to Iran, from paintings and dyes to spice and perfumes, saffron’s flavor and sparkly yellow color has made its trail in human history. As saffron crocus (Crocus sativus L.) can be traced in artworks across history, its appearance in various arts and crafts gives insights into saffron’s early geographic distribution and finally into its origin.

The Mediterranean is considered as the emergence site of many diploid Crocus species (Maw, 1886; Mathew, 1982), with Greece and Turkey possessing the highest number of Crocus taxa. Investigating ancient texts and artworks in these regions can help finding more information on early saffron domestication.

Regarding ancient texts, the first use of the word “saffron” dates back to the 12th century to the old French term safran that consecutively originated from the Latin safranum, the Arabic za’farān, and the Persian zarparan with the meaning “gold strung” (Asbaghi, 1988). As folk taxonomies were used to differentiate plant species prior to the formalization of the Linnaean system, different species of purple, autumn-flowering crocuses were not distinguished before the 18th century (Day, 2011a). Hence, at the time, most crocuses were considered as one and we cannot rely on texts for clear species information. Nevertheless, Caiola and Canini (2010) suggested that Crocus cartwrightianus, Crocus thomasii, or Crocus hadriaticus were the most likely species that were cited by ancient historians.

Regarding ancient arts, images can be categorized into two types: On one hand, those that are painted using pigments derived from crocus and on the other hand, those that depict saffron crocus flowers. The first type of image can give us information about the probable timeline of saffron use, whereas the second may give us information about its origin as it provides access to the morphological aspects of the crocus species used at the time. The major difference here is that one type provides scientific evidence for the time scale, whereas the other type leaves room for interpretation and speculation. Hence, the visual analysis depends on multiple aspects like placing the art in the socio-historical context, knowledge on artistic techniques as well as possible restoration approaches.

While the use of crocus-based pigments can be traced back about 50,000 years ago to prehistoric cave paintings in northwestern Iran (today’s Iraq; Humphries, 1996; Figures 1A,B), early signs of cultivation and domestication were found later, at about 1700 before the common era (BCE), during the time of the Minoan civilization in Crete (Deo, 2003; Dewan, 2015). As saffron’s high medicinal value and antioxidant ability were recognized, its commercial value as a spice increased over the next eras, leading to its spread across the Mediterranean (Abrishami, 2004; Caiola and Canini, 2010).

Although saffron is in high demand as spice and colorant these days, its cultivation still relies on traditional knowledge and has remained largely untouched by industrialization. This is rooted in saffron’s genetic constitution as a male-sterile triploid, which can only be propagated vegetatively. Currently, any alteration in saffron production also requires change in its vegetative propagation and quality control (Caiola and Canini, 2010). In contrast, sexual propagation of saffron would result in new, desirable traits, but would involve the selection of parental genotypes. To inform the required selection process, knowledge of saffron’s genetic and geographic origin is crucial. To fill this gap, over the last decade, several studies have attempted to resolve saffron’s domestication and to clarify its auto- or allopolyploid origin.

Here, we illustrate how the insights gained from ancient artworks add to our knowledge of saffron’s origin, how they compare with the recent genetic approaches, and how they can steer further research on saffron evolution, domestication, and breeding. For this, we build on our previous work (Schmidt et al., 2019), in which we have used cytogenetics to derive the genetic origin of saffron from cytotypes of C. cartwrightianus, thereby excluding other Crocus species as parental contributors to its triploidy. In the related paper of Nemati et al. (2019), genotyping-by-sequencing (GBS) has been used to independently reach the same conclusion and to trace the genetic origin of saffron’s triploidy back to Greece. Now, we have combined forces to put the results of saffron’s genetic origin into the broader context with ancient arts. Especially as no ancient saffron samples have been uncovered from the Aegean time—that may potentially harbor aDNA—the ancient artworks are currently the only waypoints that may guide modern genomics efforts to fill in the remaining holes in saffron’s history: We go through time and explain how and where saffron use (and the use of other Crocus species) was described or depicted and compare the results with current genomics efforts. We put on a wider lens and draw a comprehensive picture of the current view on saffron’s history, as well as lay out what gaps are still open to be addressed in the future.

Evidence for the use and cultivation of saffron have been found across different cultures and times. Here, we will follow saffron’s traces across ancient artworks in a chronological manner.

The oldest evidence of crocus usage through mankind was detected in a 50,000-year-old depiction of beasts in a cave in today’s Iraq, where saffron-related pigments (including crocin) have been used (Caiola and Canini, 2010). Wild-grown “historic saffron” (“historic saffron”: any crocus species with at least partially similar traits as today’s cultivated saffron and used by humans for this particular trait) was reported to have been used by Sumerians (ca. 4100–1750 BCE) as part of their remedies and medical potions (Willard, 2002). Also, royals of old Assyria and Babylonia (2nd millennium BCE) used “historic saffron” as a treatment for several diseases and had their courts filled with textiles dyed with “historic saffron” or later possibly cultivated saffron, which were supplied by Phoenician traders (Basker and Negbi, 1983; Mousavi and Bathaie, 2011; Dewan, 2015).

The most prominent pictures of potentially cultivated saffron in historic artworks were created during the Aegean Bronze Age, particularly influenced by the Minoan civilization, dating back to 1700–1500 BCE (Deo, 2003; Dewan, 2015). Important excavation sites are located on the islands of Crete and Thera (today’s Santorini) both belonging to today’s Greece. For this review, we will mainly focus on the crocus depictions in ancient frescoes, but will also address ceramics and cloth found in Akrotiri (Thera) and Knossos (Crete; Warren, 2005).

The most relevant representations for our review show the gathering of saffron (Figures 1C,D) and its usage in cultural rituals on multiple frescoes. These were found in remains of historical buildings (“Xeste 3,” “West House,” and others) in Akrotiri. The oldest saffron-depicting fresco (“The Saffron Gatherers,” sometimes referred to as “Blue Monkeys/Boys” fresco); however, was found in the so-called House of Frescoes in Knossos and was dated to approximately 1700 BCE. With the amount and prominence of saffron flowers depicted, these frescoes clearly demonstrate the importance of saffron around 1700–1500 BCE in the Aegean Bronze Age (Dewan, 2015).

The crocuses depicted on the frescoes in Xeste 3 show distinctive similarities with modern cultivated saffron (C. sativus) such as their long and intensively red stigmas overtopping the dark violet petals. These visual characteristics are also found on other artistic representations of crocus flowers on ceramics and cloth (Day, 2011b; Dewan, 2015; Marinatos, 2015). Typical for this time was the syllabic script Linear B (Shelmerdine, 1998). The ideogram (script character) representing saffron shows very long stigmas overtopping three pictured petals (Day, 2011a; Dewan, 2015) matching all afore-mentioned representations as well as today’s cultivated saffron. This leads to the assumption that most likely all depicted phenotypes across Akrotiri and other excavation sites belong to only a single Crocus species. It is particularly striking that these representations seem to show remarkable differences compared to most of the Crocus species natively occurring on Crete and the surrounding islands today, such as Crocus boryi, Crocus oreocreticus, Crocus sieberi, Crocus tournefortii, Crocus laevigatus (Greece mainland and Santorini), Crocus ruksansii (Karpathos), Crocus rhodensis (Rhodes), Crocus mazziaricus, Crocus olivieri, and Crocus pallasii (Greece to Turkey; Rukšāns, 2017). The only exception here is C. cartwrightianus (Crete to Greece mainland), which itself shows a huge variety of differing phenotypes and is also sometimes referred to as wild saffron (Larsen et al., 2015; Rukšāns, 2017; Nemati et al., 2019; Schmidt et al., 2019). Some of the C. cartwrightianus phenotypes found today look very similar to those depicted in the ancient frescoes. Hence, archeologists and (paleo-)botanists classified the flowers depicted in the frescoes as either C. sativus or C. cartwrightianus (Möbius, 1933; Warren, 2000; Day, 2011a).

No remains of bulbs or other parts of the actual plants have been found in the various excavation sites making it impossible to verify which species was depicted on the artistic works (Day, 2013). The chances to find any remains in the future seem very low considering that volcanic activities (“Minoan eruption”) destroyed major parts of the island Thera (Friedrich, 2009). During this geographical event also the surrounding islands including Crete have been influenced by earthquakes and tsunamis (Friedrich, 2009).

The importance of crocus use as highlighted on the frescoes in Xeste 3 allow for some speculation: The depicted crocus plants are often planted in clumps that could be interpreted as a sort of cultivation (Morgan, 1988; Figure 1C: “The Saffron Gatherers”). Moreover, the previously mentioned Linear B tablets also include information on large amounts of traded saffron, with many dedicated fabric-processing tools found in Akrotiri (Day, 2011a). Additionally, its theorized, cosmetic use for the coloring of lips and ears during festivities was also depicted in the “Young Priestess” fresco (West House, Akrotiri; Ferrence and Bendersky, 2004; Day, 2011a; Dewan, 2015). This suggests that saffron was economically important, already forming a specialized branch of industry. Likely, this also implies that saffron collection from the wild was insufficient to meet the high demands for saffron as spice, dye, and cosmetic product, but that saffron was instead cultivated in gardens or fields.

One of the frescoes in Xeste 3 termed the “Adorants” fresco (Figure 1D) clearly shows a crocus flower harboring all typical saffron crocus traits with the bright orange/red stigmas highlighted. The woman sitting has a cut in her foot with a saffron flower depicted below. There are two interpretations on the meaning of this fresco discussed in the literature. One is that the blood colors the saffron’s stigmas red which might be seen as a sign of reaching female adulthood including menstruation (Rehak, 2004; Dewan, 2015). Others argue that the women is a goddess and the flower grows from her wounded foot (Marinatos, 2015). While both is possible, we argue that this could indeed symbolize the human-led saffron domestication efforts in the Aegean Bronze Age. In the later Minoan ages, frescoes of saffron became less common, but it continued to be depicted on remains found of all kinds of ceramics and clothing (Ferrence and Bendersky, 2004; Day, 2011a; Dewan, 2015).

Despite the most reliable evidence of the cultivation of saffron being found in the Aegean Bronze Age culture, saffron artworks have also been found around the same time in other countries, such as Egypt and Persia. In ancient Egypt, Theban tombs of five high officials whose career spanned the time from Queen Hatshepsut through the early reign of Amenophis III (New Kingdom; c. 1480–1380 BCE) depict men carrying textiles to be presented as a tribute. Style of ceilings and wall-paintings in these tombs is Aegean and reflects artistic motifs derived from saffron-colored textiles (Wachsmann and Wachsmann 1987; Barber 1991; Dewan 2015). The individuals appearing in these paintings are dressed in a stylized version of Aegean Bronze Age costumes that resemble those in the Procession Fresco from Knossos (Rehak 1996). The adjacent hieroglyphic inscriptions which appear above those men geographically identifies them as Aegean natives, the Keftiu, which is the Egyptian name for Crete, and describes them as people living in the “Islands in the midst of the sea” (Wachsmann and Wachsmann, 1987; Barber, 1991; Panagiotopoulos, 2002; Matić, 2019). Although no record of saffron cultivation by Ancient Egyptians can be found, detailed historic information of saffron usage for several medical purposes is mentioned in the Papyrus Ebers (1550 BCE; Toellner, 2000; Mousavi and Bathaie, 2011). Moreover, the rareness of saffron-dyed Minoan textiles in Egypt reflects why they were considered ideal as elite gifts to Egyptian royals and support the notion that saffron products was mainly imported from Crete which was home to a thriving textile industry (Feldman, 2002; Mousavi and Bathaie, 2011; Dewan, 2015).

Historic data indicate that Persian “historic saffron” (possibly C. haussknechtii) was cultivated in Derbena, Khorasan by the 10th century BCE and also during the Median Kingdom (708–550 BCE) near Zagros and Alvand mountains, suggesting that ancient Persians were one of the early nations who cultivated saffron instead of gathering wild crocus flowers (Dadkhah et al., 2003; Caiola and Canini, 2010; Mousavi and Bathaie, 2011). The main applications of saffron in Persian art were as a dye in royal carpets and funeral shrouds as well as in paper colorings and Persian miniature paintings to prevent the corrosive effect of the verdigris pigments (Willard, 2002; Barkeshli, 2016; Dehboneh et al., 2019).

Despite these many occurrences across artworks of the ancient world, the first written evidence of cultivated saffron (C. sativus) is only found around 350–300 BCE in the Historia Plantarum (Theophrastus, n.d.; Figure 1E), where the saffron-specific propagation through corms is described in detail. Hence, understanding and interpreting the ancient arts can push this time limit back for over a millennium, assisting us in formulating theories, and enabling modern saffron genetics to follow and verify these leads.

Although saffron’s origin has been under debate for over a century, with a large body of work attempting to clarify its genetic and geographic origin (reviewed in Koocheki and Khajeh-Hosseini, 2020), the history of saffron domestication remained unresolved until recently. Instead of chromosome pairs, saffron has eight chromosome triplets with a chromosome configuration of 2n = 3x = 24 and a triploid genome size of 10.5 Gb (Chichiriccò, 1984; Brandizzi and Caiola, 1998; Agayev, 2002; Schmidt et al., 2019). Saffron’s triploidy is the cause for many genetic peculiarities of saffron.

Saffron crocus is the source of the most expensive spice in the world but is—unlike most other cash crops—inaccessible to classical breeding approaches. Investigating saffron crocus’ depictions in ancient arts and combining it with the current genetics can lead to insights into its early cultivation and geographical origin, opening up new breeding avenues for better equipped saffron varieties.

Comparing ancient arts and modern genetics gave us symmetric results: Historians cited C. sativus, C. cartwrightianus, or C. haussknechtii as the most likely species that are shown in ancient arts, including crafts from various origins (Iran, Greece, Egypt, etc.). Importantly, flowers depicted in Aegean Bronze Age frescoes were classified by archeologists and (paleo-)botanists as either C. sativus or C. cartwrightianus, showing that at least one of those species occurred in the area of today’s Greece, providing early signs of cultivation and economic relevance. For example, the “Adorants” fresco from Xeste 3 depicts crocus flowers in great detail, highlighting the typical dark-red stigmas overtopping the flower (Figure 1D), a trait that is fixed in C. sativus, but can also occur in the more variable C. cartwrightianus. Together with the clumps of flowers seen in “The Saffron Gatherers” (Figure 1C) the frescos could even be interpreted as an artistic rendition of the human influence on saffron’s domestication. Meanwhile, genetic research has provided a large body of evidence for saffron’s autotriploid origin from two different, in Greece naturally occurring, cytotypes of C. cartwrightianus using GBS and multicolor cytogenetics (Nemati et al., 2019; Schmidt et al., 2019). Hence, despite 90% of saffron being grown in Iran (Monks, 2015; Koocheki and Khajeh-Hosseini, 2020), most evidence points to its origin in early Greece. The Aegean Bronze Age artworks point to the islands of Crete and Santorini (Thera), where the most prominent frescoes can be found. Indeed, the latest GBS analysis corroborates the art-inspired focus on the Aegean area, but allows a greater precision: This genetics study shifts our attention slightly north to the region of Attica, as its modern C. cartwrightianus accessions were shown to contain 98% of all saffron alleles (Nemati et al., 2019). Ideally, to follow up these leads, plant remains from the ancient Aegean Bronze Age would be needed to confirm these hypotheses—for species identification and specifically to serve as a template for comparative ancient DNA genomics. Fossil, microfossil, herbarium material or otherwise preserved plant remains have already led to the understanding of the genetic history of several crop species (van Heerwaarden et al., 2011; Scott et al., 2019). Nevertheless, so far, no ancient crocus remains were reported that geneticists could tackle.

As discussed above, the phenotypic differences among saffron accessions likely originate from mostly epigenetic variability and do not point to multiple independent origins. In the future, comparative epigenomics will give a better understanding of saffron’s genetic and epigenetic composition, and offer new insights on its parental species contribution. Nevertheless, the generation of a full genome assembly will face considerable challenges, including saffron’s triploidy, the high level of genome heterozygosity, its large genome, and its high percentage of repetitive DNA. Similarly, the stability of saffron’s divergent phenotypes in consecutive growing seasons indicates that epigenetics may play a large role in phenotype breeding. Building on what we can learn from the ancient arts, further genomics approaches will likely result in clarifying the impact of early saffron domestication on its genome and also gives us a better outlook on the genetic and epigenetic basis of saffron’s quality traits that can be eventually implemented in the improvement of saffron quality and production.

S-SK-S, LM, and AE wrote the manuscript, created the figures, and contributed equally. TH initiated, outlined, and coordinated this endeavor. TH, BU, ZN, and DH guided the project intellectually and contributed to writing in their respective fields of expertise. All authors contributed to the article and approved the submitted version.

We acknowledge funding from the Deutsche Forschungs gemeinschaft (DFG 433081887), awarded to BU (98/21-1), TH (HE 7194/2-1), and Frank Blattner (BL 462/19-1) as well as from the Egyptian Ministry of Higher Education awarded to AE (Call 2019-2020). We also thank the Open Access Funding by the Publication Fund of the TU Dresden and Sächsische Landesbibliothek – Staats- und Universitätsbibliothek (SLUB).

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

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