It has long been dubbed "the special relationship." Six decades after the Holocaust, German officials routinely speak of a special responsibility towards the state of Israel, which rose from the ashes of the systematic extermination of six million Jews of Europe. Over the last four decades, since the establishment of diplomatic relations between Israel and Germany in 1965, Germany has proved itself to be Israel's strongest supporter and best political ally in the European Union. The relationship, which grew out of a landmark 1952 compensation agreement with the state of Israel, took decades to develop, amidst the anguish of hundreds of thousands of Holocaust survivors living in Israel and the slow historic acknowledgment within Germany of the country's crimes, with Holocaust awareness only gathering force in Germany in the 1970s. This week, German Chancellor Angela Merkel kicked off a three-day visit to Israel. In a historic address at the Knesset on Tuesday - an honor bestowed upon former German president Johannes Rau in 2000 but never before on the German chancellor - Merkel will be tested by the position she takes on Germany's economic relationship with Iran, in light of increasing Israeli concerns over Iran's nuclear weapons program. "You cannot be a friend of Israel and be indifferent to Iran's nuclear program," said Dr. Johannes Gerster, President of the German-Israeli Friendship League. "You have to take sides with Israel and against the plan of Iran to develop the atomic bomb in the future." Gerster said it was critical for Germany to take a more active role in the European Union in favor of harsher economic sanctions against Iran - at a time when some Germany companies continue to do business with the Islamic Republic - as part of the country's historic moral responsibility to the State of Israel. "Merkel views the Iranian nuclear threat [as being] not only against Israel, but as a global threat," said former ambassador to Germany Shimon Stein. Stein said that the German leader understood the need to minimize economic and financial ties between Germany and Iran, noting that major German banks have already frozen ties with the Islamic Republic. Still, as other German companies, such as Siemens, continue to do business with Iran, the relationship between Israel and Germany will be tested in the coming weeks and months over what is viewed to be an existential threat to the State of Israel.