With the nation-building process in mid-19th century, first Croatian-Serbian tension appeared. Serbian minister Ilija Garašanin's Načertanije (1844):3 claimed lands that were inhabited by Bulgarians, Macedonians, Albanians, Montenegrins, Bosnians, Hungarians and Croats were part of Serbia.:3 Garašanin's plan also includes methods of spreading Serbian influence in the claimed lands.:3–4 He proposed ways to influence Croats, who Garašanin regarded as "Serbs of Catholic faith".:3 This plan considered surrounding peoples to be devoid of national consciousness.:3–4:91Vuk Karadžić in the 1850s then denied the existence of Croatians and Croatian language anywhere in the Balkans, save for some of the northern parts of Slavonia. Those living in the Balkans, he labeled as Serbs. Croatia was at the time a kingdom in Habsburg Monarchy, with Dalmatia and Istria being separate Habsburg Crown lands. Ante Starčević, head of the Croatian Party of Rights, advocated for Croatia as a nation. After Austro-Hungary occupied Bosnia and Herzegovina in 1878 and Serbia gained its independence from Ottoman Empire, Croatian and Serbian relations deteriorated as both sides had pretensions on Bosnia and Herzegovina. In 1902 there was a reprinted article written by Serb Nikola Stojanović that was published in the publication of the Serbian Independent Party from Zagreb titled Do istrage vaše ili naše (Till the Destruction, ours or yours) in which denying of the existence of Croat nation as well as forecasting the result of the "inevitable" Serbian-Croatian conflict occurred.
That combat has to be led till the destruction, either ours or yours. One side must succumb. That side will be Croatians, due to their minority, geographical position, mingling with Serbs and because the process of evolution means Serbhood is equal to progress.
— Nikola Stojanović, Srbobran, 10.08.1902.
During the 19th century, some Italian radical nationalists tried to promote the idea that a Croatian nation has no sound reason to exist: therefore the Slavic population on the east coast of the Adriatic Sea (Croats and Slovenes) should be Italianized, and the territory included in Italy.
Fascist-led Italianization, or the forced assimilation of Italian culture on the ethnic Croat communities inhabiting the former Austro-Hungarian territories of the Julian March and areas of Dalmatia, as well as ethnically-mixed cities in Italy proper, such as Trieste, had already been initiated prior to World War II. The Anti-Slavic sentiment, perpetuated by Italian Fascism, led to the persecution of Croats, alongside ethnic Slovenes on ethnic and cultural grounds.
A leaflet from the period of Fascist Italianization prohibiting singing or speaking in the "Slavic language" in the streets and public places of Dignano (now Vodnjan, Croatia). Signed by the Squadristi (blackshirts), and threatening the use of "persuasive methods" in enforcement.
In September 1920, Mussolini said:
When dealing with such a race as Slavic - inferior and barbaric - we must not pursue the carrot, but the stick policy. We should not be afraid of new victims. The Italian border should run across the Brenner Pass, Monte Nevoso and the Dinaric Alps. I would say we can easily sacrifice 500,000 barbaric Slavs for 50,000 Italians.
This period of Fascist Italianization included the banning of the Croatian in administration and courts between 1923 and 1925, the Italianization of Croat given and surnames in 1926 and the dissolution of Croatian societies, financial co-operatives and banks.
This period was therefore characterised as "centralising, oppressive and dedicated to the forcible Italianisation of the minorities"  consequently leading to a strong emigration and assimilations of Slovenes and Croats from the Julian March.
Following the Axis Invasion of Yugoslavia in April 1941, Italy occupied almost all of Dalmatia, as well as Gorski Kotar and the Italian government made stringent efforts to further Italianize the region. Italian occupying forces were accused of committing war crimes in order to transform occupied territories into ethnic Italian territories.. An example of this was the 1942 massacre in Podhum and Testa, when Italian forces murdered at least 108 Croat civilians and deported the remaining population to concentration camps.
Chetnik ideologists during World War Two contended that ethnic cleansing of certain areas was necessary to consolidate an ethnically "pure" Serb territory as a basis of post-War Yugoslavia. This ethnic cleansing was supposed to be conducted "at a convenient moment" and Croats alongside Bosniaks were to be targeted as part of this policy. One of the numerous documents that attest to this plan is Mihailović's written "instruction" to Pavle Đurišić from 20 December 1941:
The goals of our squadrons are:
A struggle for the freedom of our people under the scepter of His Majesty King Peter II,
To create Greater Yugoslavia and Greater Serbia within it, and ethnically cleansed Montenegro, Bosnia and Herzegovina, Syrmia, Banat and Bačka within Greater Serbia,
(...) 2) Regarding our internal affairs, the demarcation with the Croats, we hold that we should as soon as an opportunity occurs, gather all the strength and create a completed act: occupy territories marked on the map, clean it before anyone pulls itself together. We would assume that the occupation would only be carried out if the main hubs were strong in Osijek, Vinkovci, Slavonski Brod, Sunja, Karlovac, Knin, Šibenik, Mostar and Metković, and then from within start with an [ethnic] cleansing of all non-Serb elements. The guilty should have an open way - Croats to Croatia, Muslims to Turkey (or Albania). As for the Muslims, our government in London should immediately address the issue with Turkey. English will also help us. (Question is!). The organization for the interior cleansing should be prepared immediately, and it could be because there are many refugees in Serbia from all "Serb lands" (...).
The tactics employed against the Croats were at least to an extent, a reaction to the terror carried out by the Ustaše, but Croats and Bosniaks living in areas intended to be part of Greater Serbia were to be cleansed of non-Serbs regardless, in accordance with Mihailović's directive of 20 December 1941. However the largest Chetnik massacres took place in eastern Bosnia where they preceded any significant Ustashe operations. Chetnik ethnic cleansing targeted Croat civilians throughout areas of Croatia and Bosnia and Herzegovina, in which Croats were massacred and expelled, such as the Krnjeuša massacre and the Gata massacre. According to the Croatian historian, Vladimir Žerjavić, Chetnik forces killed between 18,000-32,000 Croats during World War II, mostly civilians. Some historians regard Chetnik actions during this period as constituting genocide.
Written evidence by Chetnik commanders indicates that terrorism against the non-Serb population was mainly intended to establish an ethnically-pure Greater Serbia in the historical territory of other ethnic groups (most notably Croatian and Muslim, but also Bulgarian, Romanian, Hungarian, Macedonian and Montenegrin). In the "Elaborate" of the Chetnik's Dinaric Battalion from March 1942, it's stated that the Chetniks' main goal was to create a "Serbian national state in the areas in which the Serbs live, and even those to which Serbs aspire (Bosnia and Herzegovina, Lika and part of Dalmatia) where "only Orthodox population would live". It is also stated that Bosniaks should be convinced that Serbs are their allies, so they wouldn't join the Partisans, and then kill them."[better source needed]
Regarding the campaign, Chetnik commander Milan Šantić said in Trebinje in July 1942, "The Serb lands must be cleansed from Catholics and Muslims. They will be inhabited only by the Serbs. Cleansing will be carried out thoroughly, and we will suppress and destroy them all without exception and without pity, which will be the starting point for our liberation. Mihailović went further than Moljević and requested over 90 percent of the NDH's territory, where more than 2,500,000 Catholics and over 800,000 Muslims lived (70 percent of the total population, with Orthodox Serbs the remaining 30 percent).
According to Bajo Stanišić, the final goal of the Chetniks was "founding of a new Serbian state, not a geographical term but a purely Serbian, with four basic attributes: the Serbian state [Greater Serbia], the Serb King [of] the Karađorđević dynasty, Serbian nationality, and Serbian faith. The Balkan federation is also the next stage, but the main axis and leadership of this federation must be our Serbian state, that is, the Greater Serbia.
A Serb flyer used during the Yugoslav Wars, calling upon all citizens of Dubrovnik to cooperate with the JNA against the Croats' "vampired fascism and Ustašism"
After Serbian President Slobodan Milošević's assumption of power in 1989 various Chetnik groups made a "comeback" and his regime "made a decisive contribution to launching the Chetnik insurrection in 1990–1992 and to funding it thereafter". Chetnik ideology was influenced by the memorandum of the Serbian Academy of Sciences and Arts. On 28 June 1989, the 600th anniversary of the Battle of Kosovo, Serbs in north Dalmatia, Knin, Obrovac, and Benkovac held the first anti-Croatian government demonstrations. On the same day, Chetnik commander from WWII Momčilo Đujić declared Vojislav Šešelj "at once assumes the role of a vojvoda and a vladika [high-ranking religious order] unifier" and ordered him "to expel all Croats, Albanians, and other foreign elements from holy Serbian soil", stating he would return only when Serbia was cleansed of "the last Jew, Albanian, and Croat".
By the end of 1991, an estimated 500,000 Croats and other non-Serbs were expelled from parts of Croatia overrun by Serb forces. 16,000 Croats (43.4% civilians) were killed during the war, largely through massacres and bombings. Croatia regained control over most of occupied territories in 1995.
The Government of Croatia contends that anti-Croat sentiment is still prevalent in Serbia.
Croatian handball fans and vehicles were attacked returning from a game in Novi Sad in 2012 by Serbian fans armed with rocks, clubs and axes.
Incidents occurred on 4 November 2015 during the Olympiakos-Dinamo Zagrebsoccer match. The Greek fans mixed with Delije supporters displayed chetnik symbols and recited slogans as "Kill the Croatian so the Albanian doesn't have a brother". The Croatian side protested to the referee and refused to play until the symbols were removed.
In July 2015, Croatian national, Tomislav Salopek, was abducted and executed in Egypt by Egyptian ISIL insurgents operating in Sinai. ISIL declared that the alleged murder of Salopek was revenge on Croatia for its participation in the international coalition against ISIL. Croatia sends small amounts of weapons like other European countries, such as Italy, Poland, Denmark and Albania.
Italian politician and President of the European Parliament from 2017-2019, Antonio Tajani, made several controversial comments regarding Croatia.In February 2019, Tajani held a speech at the National Memorial Day of the Exiles and Foibe commemoration in Basovizza (Trieste) which aroused an outrage in Slovenia and Croatia, most notably the statement "Long live Trieste, long live Italian Istria, long live Italian Dalmatia". After numerous high representatives of the two countries strongly condemned the speech for its revisionist and irredentist connotations, Tajani stated his words were intended as "a message of peace" and were misinterpreted. The Slovenian party Social Democrats launched a petition demanding Tajani's immediate resignation as president of the EU Parliament, which was signed among others by several former presidents of Slovenia and Croatia..In a March 2019 radio interview on La Zanzara, a radio show on Italian network Radio 24, Tajani discussed "the good things Mussolini did" which was likewise criticized. In a later tweet, he wrote about the alleged manipulation of his words.
In an interview with Telegraf.rs 2012 Jovan Pejin, historian and former director of the Historical Archive of Serbia, declares that "The genocidal Croats are the most primitive people in Europe ... Croatians are mostly former Serbs who separated, and as Czechs, Poles, Russians, who are themselves divided, into one nation. Croatia is an artificial creation, and everything they have achieved so far have done so on the basis of lies ... Croats speak the Serbian language, even though they only corrupt it and make it a monstrosity, and out of it is simple to conclude that they speak a perverted Serbian language ".
German left-wing philosopher Ernst Bloch described as "Kroaten als Faschisten, oder als zumindest Halbfaschisten" (Croats as fascists, or at least as semi-fascists) in an interview in 1975 for political weekly "Der Spiegel" (Der Spiegel, 6,29. Jahrgang, 03/02/1975., str. 80).
The book, "Save us, oh Lord, from the plague and Croats!", (Zagreb, 2010), collects different Anti-Croat statements,
In the media interviews 2012, the famous American singer-songwriter Bob Dylan said: "If you got a slave master or [Ku Klux] Klan in your blood, blacks can sense that. That stuff lingers to this day. Just like Jews can sense Nazi blood and the Serbs can sense Croatian blood." A legal complaint has been lodged over Dylan's remark by a Croat association in France.
In the article "Save us God of Plague, Hunger and the Croats - Ustasha mentality is as old as themselves" published in early 2014 in Intermagazin.rs, author uses - as the thruth - the writing of the Chetnik propagandist Laza M. Kostić published in USA in 1950-es: the author says (2014) it is proven the "killer mentality" is routed in Croats for centuries.
^PUŞCARIU, Sextil. Studii istroromâne. Vol. II, Bucureşti: 1926
^Regio decreto legge 10 Gennaio 1926, n. 17: Restituzione in forma italiana dei cognomi delle famiglie della provincia di Trento
^Mezulić, Hrvoje; R. Jelić (2005) Fascism, baptiser and scorcher (O Talijanskoj upravi u Istri i Dalmaciji 1918-1943.: nasilno potalijančivanje prezimena, imena i mjesta), Dom i svijet, Zagreb, ISBN953-238-012-4
^Mennecke, Martin (2012). "Genocidal Violence in the Former Yugoslavia". In Totten, Samuel; Parsons, William S. Centuries of Genocide: Essays and Eyewitness Accounts. New York: Routledge. ISBN978-0-415-87191-4.
^Tanner, Marcus (1997). Croatia : a nation forged in war. Yale University Press. p. 218. ISBN0300076681.
^Mitrović, Andrej (2007). Serbia's Great War, 1914–1918. West Lafayette: Purdue University Press. ISBN978-1-55753-476-7. Mojzes, Paul (2011). Balkan Genocides: Holocaust and Ethnic Cleansing in the 20th Century. Lanham, Maryland: Rowman & Littlefield. ISBN978-1-4422-0665-6.
^Pajović, Radoje (1977). "Kontrarevolucija u Crnoj Gori: Četnički i federalistički pokret 1941–1945" (in Serbo-Croatian). Cetinje, Yugoslavia: Obod. Cite journal requires |journal= (help)[page needed]