# Knowledge Engineering for Historians/Modelling Xmas Story
## Modelling the Christmas Story

We will now user our knowledge engineering skillz to model the Christmas stories in Matthew and Luke that a historian can compare and contrast them.

### Functional Prerequisites

Matthew and Luke want to show that Jesus of Nazareth is the Messiah. Matthew and Luke want to show that Jesus of Nazareth is the Messiah; this calls for our modal statement and projection microtheory setup.
From the Old Testament, specifically its prophecies, Matthew and Luke know that the Messiah has to be born in Bethlehem. From the historical life of Jesus of Nazareth, however, they also know that Jesus has to end up living his childhood in Nazareth — as his name suggests.

#### The Prophetic Precondition

The prophetic passage regarding the location of the birth is the prophet Micah 5:2:
   'But you, Bethlehem, in the land of Judah are by no means least among the rulers of Judah; for out of you will come a ruler who will be the shepherd of my people Israel.'
The prophetic passage regarding the virgin birth is in Isiah 7:14:
   The virgin will be with child and will give birth to a son, and they will call him Immanuel—which means, "God with us."
The critical aspects that the two gospels amalgamate from these two prophetic passages can be represented as follows:

#### The Historical Precondition

The basic problem is expressed by the following rule:
This rule explains Herodotus of Halikarnassos as well as it explains Jesus of Nazareth. Which means that the narrative of the childhood of Jesus has to be brought round to end up in the village of Nazareth in Galilee.

## The Differences in the Christmas Narratives

Now we get into the individual differences between the two narratives as provided by Matthew and Luke. It will become immediately obvious that these two narratives could not co-exist in the same context of reasoning without inducing contradictions.

### The Announcement of the Miraculous Birth

* Who is the recipient of the announcement?
* Does the announcement preceed the begin of the pregnancy?
* Where and when does the announcement occur?
Notice that the contents of the information bearing thing, the angelic message, would also be represented as a context of its own, a propositional information thing derived from the information bearing thing that is the announcement. While these announcements differ slightly, they are similar enough that for our current purposes we can use the following representational approach:
Now we get to the meat of the differences. First, the recipients are different:
Secondly, the temporal relationship to the pregnancy differs:
For right now we will gloss over the fact that one of the announcements happened inside a dream (as they always do in the Gospel of Matthew), while the other happens in broad daylight in Mary's house (which presumably means in the house of her parents). But we can capture the fact that the announcements happened in the different cities:

### Establishing the Location of the Birth

* What do Mary and Joseph have to do to be in Bethlehem?
* Where does the birth take place?
We have already pointed out that according to Matthew, Joseph and Mary lived in Bethlehem all along, which in Luke they have to travel to Bethlehem, based on a census ordered by Roman emperor August.
Now that we have the holy couple securely in Bethlehem ready to fulfill the prophecy, we can describe the birthing event.

### The First Visitors

From what has been shown so far, it should be pretty obvious how to handle the first visitors, namely the shepards in the case of Luke versus the Wise Kings or Magi from the East in Matthew. In fact, these are left as an exercise to the reader since they add nothing new in terms of how to approach this problem.

### On to Nazareth

* How direct is the route to Nazareth?
What we said above about the visitors of Baby Jesus equally applies to the eventual return to Nazareth. There is the same angelic visions in dreams in Matthew and the journeying first to Egypt and then back to Galilee (via the stop-over in Judea). Luke does not even recount the story of the return.

### A Temporal Correction

There is actually at least one subtle mistake in the representation we have given so far: specifically, we have glossed over the fact that the temporal extent of the microtheory contexts is in some cases larger than is appropriate for the facts we have stated. The indivudal events are fine — here the actor and role assignments are understood to be restricted to the temporal extent of event, not to the temporal extent of the enveloping context. But what about our residency statements regarding Joseph and Mary in the Gospel of Matthewe?
This is false, because they also reside in Egypt for a couple of years and then they move to Nazareth altogether — we already discussed this. Anything asserted in the GospelOfMatthewMt would have temporal extent to the whole of the story time as narrated, i.e. from the time of the opening geneaology to Jesus' ascension at the end of the Gospel.
In general temporal qualification is usually understood to mean mapping to an absolute timeline, like the Julian calendar.
However, for our situation this is often inappropriate; for many of the events recounted here, we do not have dates (and sometimes we might not even have rough estimates). Fortunately, temporal qualification is not restricted to absolute dates. Rather, the temporal constraints of an event can be pushed up into the temporal dimension. So we can relate the constraints in terms of story time, as long as the events themselves are temporally related to each other in terms of their sequence.