Legend
Independent
Personal union de jure
Personal union non de jure
Vassal de jure
Vassal non de jure
Tributary
Title containing zero baronies

Development of a county or barony:

(A title with no vassal baronies obviously has no development to be passed up the chain.)

The Empire of the Alps, Duchy of Tuscany, and County of Siena (1281 CE)

Holder: Ioulianos Argyros (Orthodox, Greek)

Capital: The Castle of Castello di Brolio (1 + 6 + 4 + 20 + __ under the Alps = 31+ development)

6 titles de jure under the County of Siena
The Castle of Castelnuovo Berardenga
The City of Montalcino
The Castle of Montepulciano
The Castle of Monteriggioni
The Temple of Pienza
The City of Siena
4 titles de jure under the Duchy of Tuscany
The County of Arezzo

Holder: Ioustinos of Finèl (Orthodox, Greek)

Capital: The Castle of Città di Castello (1 + 3 − 1 = 3 development)

The City of Arezzo
The Temple of Castello di Monteguarco
The City of Cortona
The County of Florence

Holder: —

Capital: The Castle of Castrum Prati (1 + 4 − 1 = 4 development)

The City of Castellina
The Temple of Fiesole
The City of Firenze
The Castle of Spedale di San Michele Archange
The County of Grosseto

Holder: —

Capital: The Castle of Castello di Monteregio (1 + 2 − 1 = 2 development)

The City of Grosseto
The Temple of Roselle
The County of Santa Fiora

Holder: —

Capital: The Castle of Arcidosso (1 + 5 − 1 = 5 development)

The City of Orbetello
The City of Pitigliano
The City of Santa Fiora
The Castle of Soana
The Temple of Sorano
20 titles de jure under the Kingdom of Italy (and 1 with no baronies)
The Duchy of Baden and County of Breisgau

Holder: Ortolf Konradiner (Orthodox, Franconian)

Capital: The Castle of Freiburg (1 + 3 + 2 − 1 = 5 development)

3 titles de jure under the County of Breisgau
The Temple of Offenburg
The Temple of Sankt Blasien
The City of Schaffhausen
2 titles de jure under the Duchy of Baden
The County of Baden

Holder: —

Capital: The Castle of Hodenhagen (1 + 4 − 1 = 4 development)

The City of Backnang
The City of Baden
The Castle of Durlach
The Temple of Pforzheim
The County of Eberstein

Holder: —

Capital: The Castle of Eberstein (1 + 1 − 1 = 1 development)

The City of Gernsbach
The Duchy of Carinthia and County of Carinthia

Holder: Lutwig fon Andechs (Orthodox, Franconian)

Capital: The Castle of Sanktveit (1 + 4 + 1 − 1 = 5 development)

4 titles de jure under the County of Carinthia
The Castle of Friesach
The Temple of Gurk
The Temple of Karnburg
The City of Klagenfurt
1 title de jure under the Duchy of Carinthia
The County of Görz

Holder: —

Capital: The Castle of Görz (1 + 2 − 1 = 2 development)

The Temple of Grado
The City of Vrtojba
The Duchy of Como and County of Castelseprio

Holder: Berardo di Stazone (Orthodox, Lombard)

Capital: The Castle of Sepiro (1 + 4 + 2 − 1 = 6 development)

4 titles de jure under the County of Castelseprio
The Temple of Aruna
The Castle of Locarn
The Temple of Turbigh
The City of Varés
2 titles de jure under the Duchy of Como
The County of Como

Holder: Polykarpos of Pforzheim (Orthodox, Greek)

Capital: Lügàn (1 + 4 − 1 = 4 development)

The Castle of Castell Baradell
The City of Comm
The Temple of Legnan
The City of Sundri
The County of Ticino

Holder: Berardo di Stazone (Orthodox, Lombard)

Capital: Belinzona (1 + 2 − 1 = 2 development)

The Castle of Muss
The Temple of Biasca
1 title non de jure under the Duchy of Como
The County of Aquileia

Holder: —

Capital: The Castle of Udin (1 + 3 = 4 development)

The Temple of Concordia
The City of Mota de Livensa
The Temple of Olee
The Duchy of Ferrara and County of Ferrara
The Duchy of Istria and County of Duino
The Duchy of Lucca and County of Volterra
The Duchy of Mantua and County of Novellara
The Duchy of Marche and County of Ancona
The Duchy of Milan and County of Milan
The Duchy of Modena and County of Reggio
The Duchy of Montferrat and County of Montferrat
The Castle of Oderso
The Duchy of Parma and County of Piacenza
The Duchy of Piedmont and County of Susa
The Duchy of Pisa and County of Pisa
The Duchy of Ravenna and County of Forli
The Duchy of Savona and County of Savona
The Duchy of Siena

Holder: —

Capital: —

The Duchy of Spoleto and County of Spoleto
The Duchy of Urbino and County of Urbino
The Duchy of Verona and County of Vicenza
?? titles de jure under the Empire of the Alps
?? titles non de jure under the Empire of the Alps