Wednesday, November 19, 2014

How confusing were the first genealogies?

In a previous post I introduced the Great Stemma as the earliest known pedigree, being a genealogical view of biblical history (The first infographic was a genealogy). In it I noted that people were enclosed in circles, which were connected by lines showing relationships, much as we still do today. However, the lines combined marriage, parent-offspring and brotherly relationships without distinction. So, while it is a good first attempt, the Great Stemma leaves room for informational confusion, and this was not corrected at any time during its centuries of being copied. (In fact, confusion was increased through embellishments, deletions and modifications; but that is another story.)

To illustrate the potential problem of interpreting this early type of genealogy, I have included here a specific example.

The above excerpt from the Stemma shows the the children of Jacob by his wife Leah (who is shown at the top centre), and their subsequent children (ie. Leah's grandchildren). I have annotated the diagram to show parent-offspring (P), brother (B) and half-brother (HB) relationships. Note that all relationships are between males unless specified otherwise (so, half-brothers have the same father).

Leah is at the top [generation 1], with her six sons in a row below her (in birth order left to right), and her daughter to the side [generation 2]. Below this is the first-born son of each of the sons [generation 3], followed in columns down the page by their later sons, in birth order. Sons by later relationships are shown as half-brothers. At the bottom are two of Leah's great-grandchildren [generation 4].

Thus, the genealogical diagram does not effectively separate the generations visually, and parental and fraternal relationships are depicted in the same way. These days we solve this, of course, by keeping each generation as a single row and linking each child directly to the parent. It is easy to get used to the Stemma way of doing it, because it is fairly consistent about the arrangement. If there is confusion, then each circle does specify the relationship in words.

So, as I noted, this is a good first attempt, but some of the things that we now feel need distinguishing were not distinguished by the (unknown) original author.

However, the 24 extant copies of the Stemma are not identical, and two of them try to fit more information into Leah's family tree than is shown above. This information concerns the origin of the fourth generation, which is accurately depicted as far as it goes, but the above figure leaves out a lot. Some of the extra information is shown in the Stemma version below, which adds two extra people, both of them wives. I have annotated this version the same as the previous one, except that this pedigree adds one more relationship to the mix — marriage (M).

The extra details come from Genesis 38, which describes a set of relationships that would make a modern television soap-opera scriptwriter jealous. The story goes something like this (I have indicated the named people with letters in the diagram above, with Leah as L):
Judah (J) marries the [unnamed] daughter (W) of Shua. Judah and his wife have three children, Er (E), Onan (O), and Shelah (S). Er marries Tamar (T), but God kills him because he "was wicked in the sight of the Lord" (Gen. 38:7). Tamar becomes Onan's wife in accordance with the custom of the time, but he too is killed by God after he refuses to father children for his older brother's childless widow, and "spills his seed on the ground" instead (Gen. 38:8-10). Although Tamar should marry Shelah, the remaining brother, Judah does not consent, for fear of his son's life (Gen. 38:11). In response, after Judah's wife has died, Tamar deceives Judah into having intercourse with her, by pretending to be a prostitute (Gen. 38:12-23). When Judah discovers that Tamar is pregnant he prepares to have her killed, but recants and confesses when he finds out that he is the father (Gen. 38:24-26). The result is twin boys, Zerah (Z) and Perez (P) (Gen. 38:27), who are accepted as Judah's sons.
Biblically, this story is important because Judah became the founder of the Tribe of Judah, one of the twelve Tribes of Israel. Their land encompassed most of the southern portion of the Land of Israel, including Jerusalem. Both the Book of Ruth and the Gospel of Matthew identify Tamar's son Perez as an ancestor of King David, which makes Judah and Tamar also ancestors of Jesus.

For our purposes here, though, the interesting thing is the confusion caused by trying to add the two marriage relationships to the pedigree. These are in no way distinguished visually from the paternal and fraternal relationships, although the circled text does specify the relationship in words. Today, we solve this potential confusion by using horizontal lines for marriage relationships and vertical lines for parent-offspring relationships.

Equally importantly, note that Tamar's (legal) relationship supplants the (biological) parent-offspring relationship between Judah and her sons — you would never conclude from the diagram that Perez was Judah's son, for example, rather than Er's. However, note the neat attempt to keep Tamar's children in a single column by putting one twin above her and one below (perhaps also signifying simultaneous birth).

The above part of this post was inspired by a blog post from Jean-Baptiste Piggin (The Tamar Storyboard). The first picture above is from an unnamed manuscript in the Biblioteca Medicea Laurenziana, Florence, Plut.20.54, dated c. 1050 AD. The second picture if from an unnamed manuscript in the Pierpont Morgan Library, New York, M.644, dated 940-945 AD.

Moving on, the scribes of that time tried to go even further in complicating simple genealogies, as shown in the next figure. This is drawn by Stephanus Garsia Placidus, and is taken from the Saint-Sever Beatus in the Bibliothèque Nationale de France, Paris, ms. lat 8878, dated c. 1060 AD.

It shows the non-Semitic (ie. polytheistic) part of Noah's family. Noah is at the top right (sacrificing two doves), with his son Japheth (J) to the left and son Ham (H) below. Their wives (W) are indicated by intersecting circles, rather than by lines, which is a more successful approach than in the Stemma. Their descendants are shown in roughly the same style as above, with the first-born son followed by the later ones in order (so that the P and B relationships are not clearly distinguished) — Japheth has seven sons and Ham has four.

However, the illustrator has also tried to include a lot of history in this genealogy. For example, the sons of Ham's son Cush end with Nimrod (N), who has a small essay attached to his name. Among other things, he founded Babel, the city that plays an important role later in the Bible. Moreover, the sons of Ham's son Canaan (C) are shown as a reticulating network rather than as a simple chain. This apparently represents their roles as founders of the 11 tribes who originally occupied the ancient Land of Canaan, and who were later driven out and enslaved by the Israelites. These lines thus represent later history rather than parental or fraternal relationships.

This diagram is thus not a simple pedigree, as we would usually leave it today.

Monday, November 17, 2014

The first infographic was a genealogy (c. 400 AD)

The New Testament was originally written in Greek, and it apparently did not occur to the writers that a visualization of the many (and lengthy) Biblical genealogies would be helpful. They knew a lot about geometry but nothing about infographics.

Given the importance of the New Testament genealogies for the foundation of Christianity (see The role of biblical genealogies in phylogenetics), it is not at all surprising that eventually someone had a go at summarizing them all in one place. However, this did not happen until several centuries later, when the Bible was being translated into Latin. Perhaps this delay had something to do with the biblical prohibition on images.

The first known attempt to draw a biblical pedigree, rather than writing out the relationships as text, also appears to have been the first attempt at a genealogy of any sort. Jean-Baptiste Piggin has been researching this document since 2009, and he has remarkably extensive notes about it at his web site Macro-Typography. Piggin dates the document to sometime in the decades before 427 AD, which is surprisingly early and thus unique in its historical context (Late Antiquity).

Importantly, the pedigree is actually an infographic in the modern sense, in that the figure itself conveys almost all of the information, with the text acting as a supplement. Thus, a single image allows the viewer to grasp the overview (of biblical history in this case), as well as providing access to the details. This is an idea that did not really catch on until the Medieval period, when Latin manuscripts started to use images as pedagogic devices, in addition to their textual descriptions. An obvious example is the so-called Tree of Porphyry in logic, which was first described in words by Porphyry of Tyre in c. 270 AD (Isagoge), sketched by Boëthius c. 520 AD (In Porphyrium Commentariorum), and finally reproduced as an actual tree diagram in Medieval manuscripts (being named arbor Porphyrii by Petrus Hispanus in 1240, in Summulae Logicales).

Sadly, there is no extant copy of this early biblical pedigree, and so we do not know who produced it or exactly when; nor do we have any of the copies made during the following 500 years. We do, however, have 24 complete or partial copies from the period 950-1250, many of them incorporated into Spanish editions of the Bible. Piggin has studied these copies extensively, and tried to reconstruct what he thinks the original document most probably looked like.

Piggin reconstructs the document (shown above), which he calls the Great Stemma, as a single scroll made from papyrus, designed to be unrolled and read from the upper left towards the middle right. All extant copies, however, break the figure up into sections, for inclusion as pages in a parchment manuscript (a codex) typical of the Medieval period.

Reconstruction was not an easy task, given the later modifications, digressions and embellishments, made with each successive hand-drawn copy. In particular, the process of reducing the long scroll to sequential pages apparently introduced many errors; and subsequent modifications degraded the logic of the original intention. Incidentally, embellishments do not improve the communication of information (see Mistaken improvements), and nor necessarily do modifications, since in this case they often created contradictions.

Above is a schematic overview of the reconstructed original scroll, but you can zoom in to all of the details by visiting Piggin's original reconstruction. Each circle represents one person (out of 540), with connecting lines showing their genealogical relationships — marriage, parent-offspring or brotherly (these are inter-mixed). Time is read left to right along the top (Adam is at the top-left), with vertical excursions downwards for lineages that do not lead to Jesus (who is at the middle-right). Note that the pedigree is drawn using nodes and lines, as we still do, but it is not drawn anything like a tree (ie. a "family tree"). Indeed, it is actually a network, since two ancestral lineages converge on Jesus (via Joseph and Mary).

The diagram also has a distinct timeline superimposed, shown as the elements without circles, which attempts to synchronize biblical events with contemporaneous secular history. So, Piggin notes that the Stemma it is "not just a genealogy, but a graphic version of the universal chronicles which attempted in antiquity to cross reference the histories of different civilizations to establish an overview of Middle Eastern and Graeco-Roman history." However, the timeline is not calibrated in any way (ie. time changes are not constant).

Below, I have included pages from some of the extant manuscripts, to show their variety after more than 500 years of scribes making copies.

The above figure is the first page from the Roda Codex, in the Real Academia de la Historia (Madrid) cod.78 (dated 990 AD). This is the start of the genealogy, with Adam at the top-left, and illustrating his family.

The above figure is the third page from an unnamed manuscript in the Pierpont Morgan Library (New York) M.644 (dated 940-945 AD). This one shows Noah and his non-Semite descendants.

The above figure is the final page from an unnamed manuscript in the Plutei collection at the Biblioteca Medicea Laurenzian (Florence) Plut.20.54 (dated 1050 AD). This shows the incarnation of Jesus, at the end of the genealogy, illustrating the confluence of the lineages described by Matthew (at the top) and Luke (at the bottom).

Piggin notes that here may actually have been few early copies of the Stemma, because of the difficulty of transcribing illustrations by hand. That is, it is very difficult to accurately hand-copy a diagram, as opposed to copying text (where only the words matter not their visual style). Indeed, to what extent did the scribes actually understand that they needed a precise copy? Copying complex technical drawings requires careful measurement and layout, and yet some of the copies seem to have been very badly planned. Piggin suggests that "the serious corruption done to the Great Stemma early in its diffusion led to it ultimately being discarded and begun all over again by medieval writers such as Peter of Poitiers." The reference is to the Compendium Historiae in Genealogia Christi by Petrus Pictaviensis (Peter of Poitiers) produced in c.1185 AD, and for which there are many extant copies dated from that time to 1650 AD.

Finally, Piggin even has a suggestion for a small ancient board game that might have provided inspiration for the form of the infographic (see Board Game). This is important, because there are no known prior models for constructing such a thing — apart from geometry, no-one had previously produced an image that illustrated non-corporeal ideas.

Footnote: The word stemma referred originally to an ancient Roman genealogy (sometimes displayed in homes), which is roughly how it is used by Piggin. However, these days the word is more commonly used in anthropology to refer to a genealogy of manuscript copies. A genealogy of manuscripts is more properly called a stemma codicum.