Some thoughts on the Alea Evangelii 19x19.
Damian Walker shows an English paraphrase of a text in the Corpus Christ College manuscript describing the tafl game Alea Evangelii here:
Looking at the diagram and putting aside the religious gobbledygook, it can be noted that -
The board consists of 19x19 lines with pieces placed in line crosses.
The lines are abrupted in the board center, there's no line cross there.
Interpretation: The center point is a forbidden point, a throne.
The four outmost points of each board corner are marked with small points, "for the decoration" says the text. This is similar to some other old tafl descriptions, where "decorated" corners mark forbidden and hostile king's squares (the "decoration" symbolizes a soldier, which again symbolizes that the square is hostile). Here in Alea Evangelii it would be a 2x2 points forbidden and hostile area in each corner.
In a number of line crosses are placed game pices. They all look the same, just black dots, except for 4 which are drawn differently, and a third type of piece in the center (the king).
There are 65 simple black dots plus the 4 special dots plus the king in center. The text however says that it should be 67 simple black dots plus the 5 specials, alltogether 72 pieces.
A tafl game should have a multiplum of 12 pieces plus one king. For Alea Evangelii it would be 48 attackers and 24 defenders plus one king, alltogether 72 pieces plus king.
In tafl the defenders should be grouped around the king in center of the board. In the diagram you find there a group of 16 dots which should thus be 16 defenders. Left are 8 defenders to place on the board.
The "decorated" corners indicate that this is a corner tafl. From experience we know that the Alea is a difficult board for the defenders, and with the setups we tested it is next to impossible if the king even has to go all the way to a corner.
So, if the 4 special dots represent pieces with extra properties, extra power, then they should be allotted to the defenders.
Left are 4 defenders to place on the board. In tafl, initial ordering should be symmetrical. To keep the symmetry they can only be placed in the 4 dots in the center lines.
Now all defenders are placed on the board.
In the circle of dots around the center, 8 of the dots are now defenders, and the other 24 dots of the circle must be attackers.
Left are 24 attackers to place on the board. In the diagram it's seen that they're grouped in the four corners, that is 6 attackers for each corner.
For some reason, the diagram shows only 5 dots in the NE corner and 4 dots in the SE corner, and though the SW corner does show 6 dots, they're placed unsymmetrically.
Only the NW corner shows the expected 6 black dots and placed symmetrically as they should be.
So it's assumed that all corners should have 6 attackers placed as shown in the NW corner.
Now to the properties of the 4 special defender pieces. The Alea description is medieval and so chess was known with it's five types of officers. However Alea could have deeper roots back to the forerunner of tafl, Ludus Latrunculorum with its one officer, the dux. The Latrunculi dux is identical to the commander piece used in the Berserk Hnefatafl 11x11. That is, it can short jump over an enemy piece.
Now bring back the religious gobbledygook. The center piece, "the primary man", "the Unity of the Trinity", is of course the Good Lord.
The 4 special pieces are the 4 Evangelists, who have extra power and of course fight on the Lord's side and thus are defenders. They are "variegated" because they are isolated defenders in an otherwise attackers' circle.
Even if the four special dots don't represent pieces of special power, so that the argument of special pieces helping the vulnerable defenders doesn't apply, even if they are just normal pieces, then they must still be alotted to the defenders, because the text says that these dots belong to the Evangelists, which again of course belong to the Lord (the king), and so they must be defenders.
So, here's my bid for the Alea Evangelii 19x19 rules:
A corner Tablut just like Brandubh and with the same rules: http://aagenielsen.dk/brandubh_rules.php
except for 2x2 size corners and 4 defending duxes.
The initial ordering is as shown on this Damian Walker's page:
The same setup is mentioned by Helmfrid as option c:
Possibly, with the 8 defenders placed in the attackers' circle, the game can work even without special duxes.
(Alternatively, a pure religous game could've been invented, where all pieces are initially black (non-believers), except for the Lord in center and 4 converted apostles (belonging to the Evangelists, the text says). And then the 4 apostles must convert rest of the board or something.)
(By the way, if "the primary man" is some other than the king in center, then he must be Jesus, and since there's only one such, and the single center point is already occupied by "the Unity", then they are forced to break the symmetry and just place the primary man somewhere on the board, and they decided of course to place him right next to an Evangelist).