The Strategic Logic of the Border Line
The Rapallo border did not merely follow the text of the treaty — behind it stood a deliberate Italian military doctrine, described in the publication La linea del confine Giulio (1930) by General Italo Gariboldi, one of the key members of the Italian delimitation delegation. According to Gariboldi, a good border combines two qualities: an obstacle for a potential aggressor and a natural divide between human communities. The terrain between the Alps and the Adriatic did not offer both qualities in one place — each section was suitable only in specific stretches.
It is essential to understand that the border does not cross a uniform alpine landscape, but two entirely different geographical zones:
- The Julian Alps in the north — classic high mountain terrain with sharp ridges, valleys and a clear watershed between the Soča and Sava rivers, or between the Adriatic and the Black Sea. Here the border logic was supposed to follow the watershed, but the Italians disregarded it as soon as they found a more favourable alignment.
- The western pre-Alpine hills and Dinaric karst plateaus in the centre and south — the Tolmin, Cerkno-Idrija and Škofja Loka hill country, deeply incised by narrow valleys and ravines. These hills are characterised by above-average slopes and very narrow valleys and gorges. The Dinaric karst plateaus are covered by extensive forests without prominent individual summits, with a sinkhole-pitted surface, sinking streams and intermittent lakes. Here the alpine logic of the watershed breaks down — there is no mountain ridge that could serve as a natural barrier in its own right.
Particularly interesting is Gariboldi's attitude towards Lake Cerknica. At first glance it would seem an ideal natural obstacle — but because it is a karst and intermittent lake that often dries out in summer, Gariboldi dismisses it as unreliable. Instead, he places the border along the eastern edge of the Snežnik plateau and draws it through Prezid down towards the Kvarner.
Cartographic Basis and Organisation of Works
Article 5 of the Treaty of Rapallo provided for three separate commissions to demarcate the border: one for the Julian March section between Italy and the Kingdom of Serbs, Croats and Slovenes, one for the territory of the Free State of Rijeka (Reka) and one for Zadar. All three operated according to the same technical procedure. The commission for the Julian March was by far the largest and most important.
For the cartographic basis, former Austria-Hungary maps at scales of 1:25,000 and 1:75,000 were used — at the time the most accurate available. The Commission transferred the border described in the treaty text onto these maps and handed them to the field sections for verification. Once the delegates had agreed in session on the alignment of each section, it was transferred to a 1:25,000 sheet and handed to field staff, who first temporarily marked the line with wooden stakes, then demarcated it permanently with concrete boundary markers.
The cartographic survey of the entire border was carried out by the Italian Military Geographic Institute in Florence (Istituto Geografico Militare, IGM). The result was 89 sheets at a scale of 1:5,000 entitled Rilievo della linea di confine e suo profilo in scala 1 : 5000 — 84 for the section north of Rubija (Rubesci) and 5 for the Rijeka territory — jointly covering the border and the border strip. Each sheet depicted approximately 3,400 m of the border line and included an elevation profile of the section with distances between boundary markers. The collection was published in two language editions between 1921 and 1926. The Yugoslav delegation received copies and on their basis prepared its own edition. The cartographic work was carried out by topographer Sgrilli, lieutenants Carasso and Monegatti, and captains di Grezia, Catardi, Latini, Covacivich, Maracci, Gallino, Lavizzari, Barbero, Barberini and Festa.
The geodetic basis of the survey was the Austrian triangulation network with its origin at the island of Ferro (El Hierro). The Commission received from the IGM three Starke theodolites accurate to two angular degrees, seven Salmoiraghi tacheometers and seven pretorian plane tables. Among the Yugoslav geodesists was also Alfonz pl. Gspan.


Four Types of Boundary Markers
For the physical demarcation of the border line, both delegations agreed on concrete boundary markers (cippi di confine) of prismatic form made of reinforced concrete, where geology permitted fixed directly onto the bedrock — so that moving or destroying them without visible traces would be nearly impossible. Four types were agreed upon:
- Principal markers (termini principali) — placed at the most important points of the border and at prominent locations, on average every 3–4 km; one metre tall. Geodetically determined with the precision of trigonometric points; Arabic numerals from north to south.
- Intermediate markers (termini secondari) — placed between principal markers to define the alignment in detail; set at every change of direction and spaced closely enough that each was visible from both its predecessor and successor. Marked with a Roman numeral within the series between two principal markers.
- Special markers (termini speciali) — placed where the border crosses significant roads; visually more prominent and of larger dimensions. A total of 38 such markers were installed.
- Tripoint marker (termine triconfinale) — a unique cylindrical marker at the summit of Peč; marking the junction of the borders of Austria, Italy and the Kingdom of SCS; erected by the Italo-Austrian commission in stone.
Inscriptions on the Markers
Each marker bore a standardised set of incised inscriptions. On the faces turned towards each respective country: the abbreviation I for Italy and SHS for the Kingdom of SCS. When in 1929 the Kingdom of SCS became the Kingdom of Yugoslavia, the new designation J was incised on newly installed or renovated markers; following the annexation of Upper Carniola by Germany in 1941, some were replaced with the designation D.
On the faces turned towards the neighbouring markers: the sequential number of that marker. Below it the year 1920 — the year of the signing of the Treaty of Rapallo. On the top face: three incised straight lines — one pointing magnetic north, and two pointing towards the preceding and following markers. These inscriptions permitted orientation without additional instruments.
The Scope of Delimitation in Numbers
Peč – Rubija
(244,523.73 m)
incl. Rijeka section
between stones
On the section between the tripoint at Peč and the border of the Free State of Rijeka, the commission installed 69 principal, 4,508 intermediate and 38 special markers. Following the annexation of the Free State of Rijeka by Italy in 1924, the Julian March border was extended to 263,934.43 m; the Rijeka section added a further 9 principal and 590 intermediate markers.
The average distance between markers was merely a guideline — in practice the distribution was extremely flexible. On the steep alpine watersheds, where the alignment was beyond doubt, markers stood up to 479 metres apart (the greatest distance between markers 12/XII and 12/XIII on the high-mountain ridge). At the other extreme, where the border wound along narrow agricultural tracks near Kastav, markers stood side by side at a distance of only 2.62 metres.
For the installation of markers, the Italians used exclusively military labour; the Kingdom of SCS, in addition to soldiers, also hired local workers. Each delegation installed approximately half of all markers — the Italians predominantly in mountain terrain, the Yugoslavs in the lowlands.
The Rapallo Border and the Land Cadastre
The Rapallo border did not emerge in an administrative vacuum — it ran across territory precisely covered by the Austrian and later national cadastral system. Digitisation of the border and georeferencing of 268 sheets of the historical land cadastre enabled a precise spatial analysis of their relationship (Žorž 2022).
The land border crossed 45 historical cadastral municipalities with a combined area of 1,366 km². On the territory of present-day Slovenia, between Peč and marker 61/LXXIX, the border runs for 215.78 km; of this, only 25.1 km (11.6%) coincides with the boundaries of the cadastral municipalities of the time. This is no coincidence — where the border followed the watersheds of the Julian Alps, it was the first demarcation to fix the relief with geodetic precision, and in doing so it frequently exceeded the cadastral boundaries, which had been only approximately drawn.
The present situation is telling: comparison of the digitised layer of the Rapallo border with the current boundaries of cadastral municipalities shows a 91.2% correspondence. The Rapallo border has thus largely become part of the cadastral structure we know today — markers that were erected as demarcations of a former state border today mark parcel boundaries on the ground.
Visibility of the Border: Clearings and Documentation
In the forested central and southern part of the border — where forest cover predominates — the markers would have remained invisible among the trees. The Commission therefore opened clearings 6 to 8 metres wide along the border line, depending on the density of the forest. The border itself runs along the middle of the clearing; this ensured the line is clearly recognisable even without markers. On the northern, high-alpine part the border follows watersheds above the tree line and no clearings needed to be cut.
For each marker, comprehensive documentation was compiled and certified by the personnel of both delegations:
- Descriptive monograph — a precise description of the course of the border line from that marker to the next, including terrain type and any special features
- Panoramic photograph — for all principal markers in two shots (summit and background) and for those intermediate markers where a photograph added information
- Three reference points — points A, B, C (clockwise) incised into the surrounding rock; the measured distances to the marker and between each other allow the exact location to be reconstructed even after possible destruction
- Sketch at 1:200 — a hand-drawn sketch of the position of the marker and reference points with a graphic representation of the terrain
- Geodetic coordinates — geographic for principal markers, graphical for intermediate markers (cadastral-order points)
- Azimuth — the angle between the direction of magnetic north and the direction to neighbouring markers, expressed numerically and simultaneously incised on the marker
All these data were entered into a joint final record book, signed after each marker by the personnel of both delegations and the supervising technician. The originals were compiled in Italian and translated into the language of the Kingdom of SCS. The Austrian trigonometric network with its origin at the island of El Hierro (Ferro) was used as the geodetic basis for the survey.
Digital Documentation — 3D Models of Boundary Markers
The Society has produced photogrammetric 3D models of all three types of Rapallo border markers as part of its documentation project. The models are accessible on the Sketchfab platform and permit detailed examination of incised inscriptions, dimensions and surface condition.
Sector boundary marker no. 52 on the slopes of the Javorniki hills between Rakov Škocjan and the summit of Čela.
↗ 3D model on Sketchfab
Special marker no. CXVIII of sector 49 — by dimensions the largest type of Rapallo border markers.
↗ 3D model on Sketchfab
Intermediate marker no. II of sector 36. The top face indicates the directions to the neighbouring markers and magnetic north.
↗ 3D model on SketchfabThe Customs Fence
Parallel to the work of the delimitation commission, the Italian Ministry of Finance — without agreement with the Yugoslav side — planned the construction of a three-metre-high metal mesh fence with locked gates at all customs crossings along the entire border. Its purpose was to stem smuggling, which had become widespread practice immediately after the border was established.
The fence was built only on the Rijeka section — along the rest of the border it was never erected. Because it had to be anchored to the ground on the Italian side, it was set slightly inward from the actual border line of the markers, which initially caused confusion about where exactly the state border ran. The fence had no connection with the work of the delimitation commission; it was a unilateral Italian infrastructure decision.
Symbolic Markers
Two markers acquired special symbolic value and were reproduced at remote locations, revealing how deeply the demarcation was inscribed in the fascist ideological project.
An intermediate marker on one of the summits of the ridge below Razor — a summit that the Italians had first traversed precisely during the delimitation work — had a replica installed at the Vittoriale in Gardone: the private museum-memorial complex of Gabriele D'Annunzio, one of the most important focal points of Italian nationalism in the interwar period.
The principal marker on Triglav was reproduced at the Redipuglia war cemetery near Monfalcone (Tržič) — the largest Italian war cemetery with 100,000 burials from the First World War. Gariboldi writes that the Italian delegation placed it there "in memory and gratitude to all those who gave their lives so that Italy would reach where the nation and history called it."
In the summer of 1919, Italian military cartographers produced a detailed map of the summit pyramid of Triglav at a scale of 1:11,000 with the watershed drawn in. The finding was unwelcome for Italy: the watershed runs west of the summit, which by consistent cartographic logic would have left Triglav entirely to the Kingdom of SCS. The summit was strategically and propagandistically crucial for Italy — soldiers reported from there on the view over the entire Ljubljana Basin.
Italy initially relied on the historical boundary between Carniola and the County of Gorizia, which ran across the very summit. This solution would have secured the summit, but access to it from the western side would have required a narrow strip with no path. As an alternative, they demanded a detailed determination of the demarcation line between Bovški Pihavec and Kanjavec — by this they had in mind control over the Bovška notch, which was at the time the only realistic route to the summit from the future Italian side. On this two-kilometre disputed section the Italians prepared five proposals, but all would have benefited exclusively them.
To secure access to the summit before official demarcation, the Italian supreme command in the summer of 1919 ordered the 52nd Division to build a mountain hut closer to the summit than any existing one. The Morbegno Alpine battalion named it after itself and ceremonially opened it in September 1919; a permanent garrison of one officer and seven soldiers was stationed there. From preserved archives it is apparent that all local place names at that time were still of Slovenian origin — Italian nomenclature was artificially introduced only by law in 1926.
Resolving the border question at Triglav required a further four years. The summit became a symbol — for Slovenes the last bastion of an already unjust border, for rising fascism a symbol of the suffering of the First World War. The Commission, politicians and press all knew that the watershed belonged to the Yugoslav side; Italy nevertheless held its ground. Colonel Daskalović clearly warned that in the event of such a demand he would refer the matter to the Swiss federal authority — the absolute mediator accepted in advance by both sides.
The decisive crisis came in July 1923. After a publication in the Trieste (Trst) newspaper Piccolo which accused the colonel of the Yugoslav section of the commission of cooperating with the nationalist organisation Orjuna, the Italian foreign ministry demanded a complete replacement of the Yugoslav members. The commission under Daskalović was replaced by Draškić from Zagreb — and shortly thereafter the border, despite the watershed, was confirmed at the very summit of Triglav. It remained there until the Paris Peace Treaty of 1947.
More on the disputes at Triglav · gore-ljudje.netSources and Bibliography
- Gariboldi, I. 1930. Lungo i confini della Patria, Fascicolo XII: La frontiera italo-jugoslava — La linea del confine Giulio. Roma: Istituto Poligrafico dello Stato.
- Commissione Italo–S.H.S. per la delimitazione dei confini. Storia della commissione e metodo del lavoro. Unpublished official report document. [Source: Storia 115–169]
- Žorž, G. 2017. Varovanje rapalske meje in vojaška navzočnost na območju XI. Armadnega zbora. Master's thesis. Ljubljana: Faculty of Arts, Department of Geography. ↗ UL Repository
- Žorž, G. 2022. Geodetska izmera rapalske meje, njena digitalizacija in presek s historičnim in aktualnim stanjem zemljiškega katastra. In: GIS v Sloveniji 16: Preteklost in prihodnost. Ljubljana: Založba ZRC, pp. 259–267. ↗ DOI
- Škodič, D. Streljanje in pleskarske vojne na Triglavu. ↗ gore-ljudje.net