Finally, the treaties established that the NDH's Ustaše regime, led by Ante Pavelić, would offer the position of the King of Croatia to a member of the House of Savoy, as appointed by Victor Emmanuel III.

The treaties, and further agreements based upon them, created resentment by the Croats, regardless of their position towards the regime, and contributed to an increasingly successful uprising against Axis occupation led by the Yugoslav Partisans.

Seeking retribution for their withdrawal from the Tripartite Pact following the Yugoslav coup d'état of March 1941, Adolf Hitler sought to politically destroy the Kingdom of Yugoslavia through dismemberment.

[1] Hitler offered Hungary the opportunity to absorb Croatia on 27 March 1941, apparently referring to the territories largely corresponding with the former Kingdom of Croatia-Slavonia.

On 29 March, however, Regent Miklós Horthy declined the offer, and Germany turned to the idea of establishing a Croatian state two days later.

The declaration was made by Slavko Kvaternik on the urging of, and with support from, SS Colonel Edmund Veesenmayer, attached to the Dienststelle Ribbentrop.

When they reached Karlovac on 14 April, however, Mussolini dispatched Filippo Anfuso by plane to intercept Pavelić and obtain a written, public confirmation that he would recognise Italian claims in Dalmatia.

[12] By 22 April, Germany posted Edmund Glaise-Horstenau as plenipotentiary general of the NDH, and Siegfried Kasche as its envoy, while Italy dispatched Raffaele Casertano as its special representative to Zagreb.

[13] Meanwhile, Hitler reversed his initial decision to leave Bosnia and Herzegovina to Italy, and foreign ministers Joachim von Ribbentrop and Galeazzo Ciano met in Vienna on 21–22 April to establish a demarcation line, splitting the NDH approximately down the middle from northwest to southeast.

When Pavelić complained that this would cost him his position, Ciano put forward another proposal, this time largely constrained to the former Kingdom of Dalmatia, accompanied by a treaty legally attaching the NDH to Italy on a military, political and economic basis.

[3] Pavelić asked Ciano to leave Split, Dubrovnik and several Adriatic islands to the NDH, and to avoid establishment of a customs union.

Ciano concurred, considering it more useful to closely tie the NDH to Italy than to outright annex a large territory containing a hostile population.

[17] The second round of negotiations took place in Zagreb between Pavelić and Casertano, and produced an agreement on 29 April to appoint a prince of the House of Savoy as the king of Croatia.

[21] In the north, the border was drawn to give Italy the cities of Kastav, Sušak, Fužine, Čabar, Bakar and a part of the Delnice district.

[24] Only hours before signing of the treaties, Pavelić formally requested Victor Emmanuel III to appoint a member of the House of Savoy to become the king of Croatia as previously agreed.

The decision to reoccupy the NDH was purportedly motivated by the intention to counter Yugoslav Partisan guerillas, but it also served to deter German access to the Adriatic.

The full takeover of the Zone II gave Italy control over the territory requested by Ciano during the negotiations in Ljubljana in April 1941.

[31] In June 1942, Italian forces withdrew 70–80 battalions of 200 stationed in the Zones II and III, choosing to garrison large population centres and major routes of transport only.

[32] The withdrawal led the Italians to rely on the Anti-Communist Volunteer Militia, largely composed of Chetniks, as auxiliary units for anti-guerrilla warfare.

[33] When Italian troops retreated after defeats in the 1942 Montenegro offensive and in the Operation Alfa, Partisans exploited the pullout, retaking the town of Bihać and surrounding parts of Zones II and III in November 1942.

[37] In his declaration, Pavelić also announced annexation of areas previously outside of Yugoslavia; specifically, Zadar, Rijeka and the Croatian part of Istria.