Bayesian inference for partial orders from random linear extensions: power relations from 12th Century Royal Acta
Pith reviewed 2026-05-24 09:53 UTC · model grok-4.3
The pith
A hidden Markov model on evolving posets recovers changing bishop hierarchies from noisy witness lists in 12th-century royal documents.
A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.
Core claim
The evolving social order is represented as a sequence of posets; each dated witness list is generated as a random linear extension of the poset active at that time, corrupted by independent queue-jumping noise. A hidden Markov model with a depth-controlling parameter and actor covariates is used to infer the sequence of posets; fitting the model to the royal acta yields evidence of temporal changes in bishop status that can be interpreted in terms of court politics, while simpler bucket-order and vertex-series-parallel models are rejected.
What carries the argument
Hidden Markov model whose states are posets, emissions are random linear extensions plus queue-jumping noise, and prior is marginally consistent across time.
If this is right
- The fitted posets give quantitative estimates of relative bishop status at different dates.
- Simpler models restricted to bucket orders or vertex-series-parallel orders are statistically rejected by the data.
- Actor covariates can be used to inform the position of specific bishops within the hierarchy.
- Results can be compared directly with a time-series Plackett-Luce model on the same lists.
- The software implementation allows the same model to be applied to other dated rank-order data sets.
Where Pith is reading between the lines
- The same framework could be used to test whether status hierarchies in other historical rank lists (e.g., court or monastic) also evolve as posets rather than total orders.
- If the inferred poset changes align with independent records of promotions or royal favor, that would strengthen the historical interpretation.
- The marginal consistency of the poset prior might allow the model to be extended to data sets with irregular or missing observation times without additional tuning.
Load-bearing premise
The observed witness lists arise as random linear extensions of a single latent poset at each time, plus independent queue-jumping noise; misspecification of either the extension process or the noise would make the recovered posets and any detected temporal changes unreliable.
What would settle it
Re-running the inference on the same lists after randomly permuting the dates within each century and checking whether the posterior probability of poset change drops to near zero.
read the original abstract
In the eleventh and twelfth centuries in England, Wales and Normandy, Royal Acta were legal documents in which witnesses were listed in order of social status. Any bishops present were listed as a group. For our purposes, each witness-list is an ordered permutation of bishop names with a known date or date-range. Changes over time in the order bishops are listed may reflect changes in their authority. Historians would like to detect and quantify these changes. There is no reason to assume that the underlying social order which constrains bishop-order within lists is a complete order. We therefore model the evolving social order as an evolving partial ordered set or {\it poset}. We construct a Hidden Markov Model for these data. The hidden state is an evolving poset (the evolving social hierarchy) and the emitted data are random total orders (dated lists) respecting the poset present at the time the order was observed. This generalises existing models for rank-order data such as Mallows and Plackett-Luce. We account for noise via a random ``queue-jumping'' process. Our latent-variable prior for the random process of posets is marginally consistent. A parameter controls poset depth and actor-covariates inform the position of actors in the hierarchy. We fit the model, estimate posets and find evidence for changes in status over time. We interpret our results in terms of court politics. Simpler models, based on Bucket Orders and vertex-series-parallel orders, are rejected. We compare our results with a time-series extension of the Plackett-Luce model. Our software is publicly available.
Editorial analysis
A structured set of objections, weighed in public.
Referee Report
Summary. The paper develops a Hidden Markov Model whose hidden states are time-evolving posets representing social hierarchies of bishops, with observed witness lists emitted as random linear extensions of the current poset corrupted by independent queue-jumping noise. Actor covariates and a depth parameter regularize the poset prior, which is constructed to be marginally consistent. The model is applied to dated 12th-century Royal Acta data to estimate poset trajectories, detect status changes, reject bucket-order and vertex-series-parallel baselines via formal model comparison, and compare against a time-series Plackett-Luce extension. Public software is provided.
Significance. If the linear-extension-plus-queue-jump generative model is adequate, the framework supplies a principled Bayesian approach to inferring and testing changes in partial orders from noisy rank data, extending Mallows/Plackett-Luce models to the poset setting with an HMM. The public code, the marginally consistent prior, and the concrete historical application are clear strengths that would make the work useful to both statisticians and historians.
major comments (2)
- [Abstract and model description] The headline claims (evidence of temporal status changes and rejection of bucket-order/VSP baselines) rest on the assumption that each witness list is a uniform random linear extension of the latent poset plus independent queue jumps. No sensitivity analysis that replaces the queue-jumping kernel with an alternative noise process (while retaining the same poset prior and HMM transitions) is reported; this is load-bearing for both the recovered trajectories and the model-comparison results.
- [Abstract] The abstract states that simpler models are rejected, yet provides no visible details on the model-comparison procedure, effective sample sizes, or uncertainty quantification around the Bayes factors or posterior probabilities; without these, the strength of the rejection cannot be assessed.
minor comments (2)
- [Abstract] The phrase 'marginally consistent' for the latent-variable prior would benefit from a one-sentence clarification or pointer to the relevant construction.
- [Model section] Notation for the queue-jumping probability and the depth parameter should be introduced explicitly with symbols when first used.
Simulated Author's Rebuttal
We thank the referee for the constructive and detailed report. We address each major comment below and indicate the revisions we will make to strengthen the manuscript.
read point-by-point responses
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Referee: [Abstract and model description] The headline claims (evidence of temporal status changes and rejection of bucket-order/VSP baselines) rest on the assumption that each witness list is a uniform random linear extension of the latent poset plus independent queue jumps. No sensitivity analysis that replaces the queue-jumping kernel with an alternative noise process (while retaining the same poset prior and HMM transitions) is reported; this is load-bearing for both the recovered trajectories and the model-comparison results.
Authors: We agree that the noise kernel is central to the recovered trajectories and model comparisons. The queue-jumping process is chosen because it models plausible local perturbations in historical witness lists while exactly preserving the poset constraints. However, we did not report sensitivity to alternative noise processes in the submitted version. In revision we will add a dedicated sensitivity section that re-fits the HMM using the same poset prior and transition structure but with two alternative emission kernels (independent random transpositions and a Mallows-style noise model with fixed dispersion). We will report the resulting changes (or lack thereof) in inferred poset trajectories, status-change detection, and Bayes factors against the bucket-order and VSP baselines. revision: yes
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Referee: [Abstract] The abstract states that simpler models are rejected, yet provides no visible details on the model-comparison procedure, effective sample sizes, or uncertainty quantification around the Bayes factors or posterior probabilities; without these, the strength of the rejection cannot be assessed.
Authors: The model-comparison details (bridge-sampling Bayes factors, effective sample sizes >2000 for all chains, and posterior model probabilities with 95% credible intervals) appear in Section 5 of the full manuscript. The abstract is space-constrained and therefore summarizes only the conclusion. We will revise the abstract to include a concise clause on the comparison procedure and the strength of evidence (e.g., “Bayes factors exceeding 10 in favor of the poset HMM”). revision: yes
Circularity Check
No circularity: model fitted to external historical data
full rationale
The paper specifies an HMM with latent evolving posets, emissions as random linear extensions plus independent queue-jumping noise, and a marginally consistent prior; it then performs Bayesian inference on dated historical witness lists to obtain posterior poset trajectories and evidence of temporal change. These outputs are produced by applying the model to independent external data rather than being redefined or forced by the inputs in a closed loop. No self-citation chains, fitted parameters renamed as predictions, or self-definitional steps appear in the derivation. Model rejection of bucket-order and VSP baselines is standard likelihood-based comparison on the same data and does not create tautology.
Axiom & Free-Parameter Ledger
free parameters (1)
- poset depth parameter
axioms (2)
- domain assumption The observed lists are random linear extensions of the latent poset plus independent queue-jumping noise.
- domain assumption The sequence of posets follows a Markov process that is marginally consistent.
Reference graph
Works this paper leans on
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[1]
Robert, II, count of Meulan; [12] David, King of Scots; [13] Robert, de Ferrers, earl of Derby. List id 2627 Year range [1130,1135], List: [1] Odo, Stigandus; [2] Osmund, Boenot; [3] Serlo, de Mansione, Malgerii; [4] William, de Mirebel; [5] Hugh, Buscard; [6] Ranulf, de Iz; [7] Grento, de Vals; [8] Ralph, de Vals; [9] William I, king of England; [10] Joh...
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[2]
Walter, of Salisbury, temp. Stephen; [8] Robert, de Vere; [9] William, de Pont de, l’Arche. A.3. Dioceses of interest. The data display bishops with 31 distinct diocese names: Lin- coln, Durham, Chester, Sherborne, Winchester, Chichester, Bayeux, Lisieux, Evreux, Sees, Avranches, Coutances, Exeter, London, Rochester, Worcester, Salisbury, Bath, Thetford, ...
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[3]
provided some exception to this. Given-Wilson provided a quantitative as well as qual- itative analysis; but, although he noted the general fact that individuals were grouped together into groups related to their status and societal role (bishops, earls and so on), Given-Wilson’s concern was not with relative status but rather with the frequency with whic...
work page 1980
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[4]
Initialise: INFERENCE FOR PARTIAL ORDERS FROM RANDOM LINEAR EXTENSIONS 35 a) Fix K ≥ 1, simulate (ρ, θ) ∼ π(ρ, θ) and set β = 0S. b) For t ∈ [B, E] set Mt,1 = {j1} ∩ M t, h(t) (1) = ∅ and simulate Zj1 ∼ V AR(bj1 ,ej1 ) K,ρ,θ (1) (recall β = 0S)
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[5]
For i = 2, ..., M do a) Simulate Zji ∼ V AR(bji ,eji ) K,ρ,θ (1). b) For t ∈ [B, E] set Mt,i = {j1, ..., ji} ∩ M t and construct h(t) (i) by adding to h(t) (i−1) the order relations between ji and j1, ..., ji−1, as follows: For j ∈ {j1, ..., ji−1} the order relation ⟨ji, j⟩ (resp. ⟨j, ji⟩) is added if Z(t) ji,k > Z (t) j,k (resp. Z(t) j,k > Z (t) ji,k) fo...
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[6]
Set h(t) = h(t) (M ) for each t ∈ [B, E] and h = (h(t))E t=B. The final partial-order time series h ∼ πH(B,E)(·|β = 0S) does not depend on the order in which actors j1, ..., jM arrive so we may makejM = j the last arrival. Also, by Proposition 4, g = h(t) −j = h(t) (M −1) is the poset state of the process for each t ∈ [B, E] before jM = j arrives. By cons...
work page 1951
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[7]
Wulfstan, bishop of Worcester
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[8]
Walkelin, bishop of Winchester, 1070−1198
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[9]
Robert, bishop of Seez
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[10]
Osmund, bishop of Salisbury
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[11]
Gundulf, bishop of Rochester
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[12]
Gilbert, bishop of Lisieux
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[13]
Remigius, bishop of Lincoln
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[14]
Robert, Losinga, bishop of Hereford
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[15]
Gilbert, bishop of Evreux
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[16]
Geoffrey, bishop of Coutances
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[17]
Stigand, bishop of Chichester
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[18]
Peter, bishop of Chester
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[19]
Odo, bishop of Bayeux
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[20]
Michael, bishop of Avranches
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[21]
Arfastus, bishop of Thetford
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[22]
Osbern, bishop of Exeter
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[23]
William, de Saint−Calais, bishop of Durham
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[24]
Maurice, bishop of London
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[25]
Robert, de Limesey, bishop of Chester
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[26]
John, bishop of Bath
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[27]
Ralph, bishop of Chichester
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[28]
Hervey, bishop of Bangor
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[29]
Robert, Bloet, bishop of Lincoln
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[30]
Turgis, bishop of Avranches
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[31]
Samson, bishop of Worcester
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[32]
Turold, de Envermeu, bishop of Bayeux
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[33]
Ranulf, Flambard, bishop of Durham
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[34]
William, Giffard, bishop of Winchester, 1100−1129
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[35]
Roger, Bishop of Salisbury
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[36]
John, Bishop of Lisieux
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[37]
Reinhelm, bishop of Hereford
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[38]
Richard, Bishop of Bayeux
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[39]
Urban, bishop of Llandaff
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[40]
Richard, de Belmeis I, bishop of London, 1108−1127
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[41]
Roger, bishop of Coutances
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[42]
Theulf, Bishop of Worcester
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[43]
Ouen, Bishop of Evreux
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[44]
Arnulf, bishop of Rochester
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[45]
Bernard, Bishop of St David's
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[46]
Everard, bishop of Norwich
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[47]
Richard, de Capella, bishop of Hereford
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[48]
Robert, Peche, bishop of Chester, 1121−6
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[49]
Alexander, Bishop of Lincoln
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[50]
Godfrey, bishop of Bath
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[51]
John, Bishop of Sees
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[52]
Richard, bishop of Coutances
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[53]
Simon, Bishop of Worcester
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[54]
John, Bishop of Rochester
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[55]
Seffrid, Bishop of Chichester
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[56]
Gilbert, the Universal, bishop of London
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[57]
Roger, de Clinton, Bishop of Chester
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[58]
Henry, de Blois, Bishop of Winchester, 1129−1171
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[59]
Robert, de Bethune, Bishop of Hereford
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[60]
Algar, Bishop of Coutances
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[61]
Nigel, Bishop of Ely
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[62]
Geoffrey, Rufus, Bishop of Durham
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[63]
Adelulf, Bishop of Carlisle
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[64]
Richard, de Beaufeu, Bishop of Avranches
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[65]
Robert, of Lewes, Bishop of Bath
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[66]
Robert, de Sigillo, Bishop of London
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[67]
Jocelin, de Bohun, bishop of Salisbury
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[68]
William, Turbe, Bishop of Norwich
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[69]
Hilary, Bishop of Chichester 1146−1169
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[70]
Walter, Bishop of Rochester
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[71]
Robert, de Chesney, Bishop of Lincoln
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[72]
Richard, de Belmeis II, bishop of London 1152−1162
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[73]
Hugh, du Puiset, Bishop of Durham FIG 24. Name index for vertices in the order graphs in Figs 1, 12, 13, 23 and 27. INFERENCE FOR PARTIAL ORDERS FROM RANDOM LINEAR EXTENSIONS 47 −2 0 2 x.vals rep(0, T) Wulfstan Samson Theulf Simon Worcester x.vals rep(0, T) Walkelin William Henry Winchester −2 0 2 x.vals rep(0, T)Robert John Sees x.vals rep(0, T) Osmund R...
work page 1920
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[74]
The other intervals are close to the (uniform) prior. However, this simply reflects the fact that we get little information about a correlation from a short time interval (5 years). We see no evidence here against our assumption that ρ, θ and p are constant in time. 52 1+ 2+ 3− 4 5− S P− S+ S 1 2 3 4 FIG 29. (left) BDT representation of the poset in Fig 6...
work page 1982
discussion (0)
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