IT’S not every day a country declares war on perhaps it’s wealthiest and most generous son.

But that’s exactly what’s happened in the case of famed Hungarian-American billionaire George Soros and his native Hungary — forcing the European Union to intervene.

On Monday, Hungarian leader Viktor Orban welcomed Israeli Prime Minister Benjamin Netanyahu to the country. The visit follows claims Orban had stoked anti-Semitism by printing huge billboards of Soros and plastering them around the country.

While the posters have since been taken down, the visit pits right-wing leaders Orban and Netanyahu against the famous Jewish businessman and philanthropist who fled the Nazis and moved to America.

Here’s what you need to know about the country that waged war on a billionaire:

WHO IS GEORGE SOROS?

Now 86, Soros fled the Nazi occupation and moved to London before emigrating to the US where he launched a hedge fund, famously pocketing $1 billion in currency speculation against the Bank of England in 1992.

He’s now worth an estimated $31 billion and is one of the largest funders of non-governmental activities and civil society across Hungary through his Open Society Foundations. He has given away $15 billion campaigning for democracy and a range of other issues.

However it’s his work with refugees that have made him a target of the Orban government.

Last year, Soros pledged $500 million to support refugees and said Europe should accept “several hundred thousand fully-screened refugees through an orderly process of vetting and resettlement.”

That contrasts with the Orban government who want to ban freedom of movement and have called refugees a “trojan horse” of terrorism and security. They’ve also made much of claims Soros wants to bring “a million illegal immigrants” to the country, something Soros has dismissed as “fantasy”.

CONTROVERSIAL BILLBOARDS

The standoff led to a $12 million government campaign with the smiling face of the Jewish businessman, warning voters “Let’s not let Soros have the last laugh.”

Jewish groups said the poster was anti-Semitic, playing on the “laughing Jew” stereotype and was part of a mentality Soros had fled from as a child. His spokesman said the posters were “reminiscent of Europe’s darkest hours”.

They’ve since been taken down (with plenty removed by activists) but despite the alleged anti-Semitism, Israel has maintained its support for the Hungarian government, saying it did not want to “delegitimize” criticism of Soros.

Meanwhile, the European Union has launched legal action against Hungary over new laws targeting civil society groups that receive money from overseas.

The EU thinks it will restrict them from being able to work, while Hungary said it wants increase the transparency of such groups.

Hungary has one month to reply to the Commission’s arguments and both cases could be eventually referred by the Commission to the EU Court of Justice.

Soros’ Open Society Foundation has slammed the decision to target civil society groups as a “serious attack on Hungarian democracy.”

European director Goran Buldioski said the law “undermines the fundamentals” and people are being misled by the government.

Peter Nizak, head of Open Society’s work in Hungary said: “We continue to believe in the rule of law and democracy in Hungary and endorse the actions of those NGOs who have said they will challenge its legality; the NGOs that will be particularly hard hit by this discriminatory and unnecessary law have our full solidarity.”

— with wires