Noting how in his March speech Francis pointed out that the six "founding fathers" of the E.U. "were all engaged in, in a personal view of course, the Catholic religion, in Christianity," Zeller said that to present this view is "very important right now," as Europe is re-thinking its identity.
Both Zeller and Habsburg stressed the importance of remembering Europe's Christian roots.
It's crucial to introduce ideas based on "common heritage, on cultural roots," Zeller said, and voiced his excitement at having the opportunity for leaders and politicians to have an open discussion about Europe, "which actually is not doing very well."
"The E.U. faces real and difficult challenges now," he said, so the idea of having a meeting among the episcopal conferences in Europe as well as political leaders is "very interesting and we are happy as European ambassadors to the Holy See to be associated and to share the views of these different conferences."
Likewise, Habsburg said he believes that for Europe truly to advance, it must "go back to core values, and some of those core values, in my opinion, are the Christian roots of Europe."
Both family and solidarity are two key values that need to be re-emphasized today, he said, adding that there has to be a careful balance "between doing things together and having a healthy respect of the differences."
In terms of the message each country wants to bring to the discussion table, Madigan, Habsburg, and Zeller all voiced their desire to both share their own local experience on key issues, and to listen.
For France, Zeller said their new president, Emmanuel Macron, has a lot of ideas on the challenges Europe faces, including security and defense policies, economic and business policies, as well as the desire to reduce unemployment and increase trade opportunities.
"It's interesting for us to see that those ideas presented by our new president and government could be shared or could trigger some ideas" within the E.U., he said, and pointed to what he believes is a need to "re-introduce this aspect of common values."
As for Ireland, which in many ways is facing a heightened sense of national uncertainty following the 2016 Brexit vote, Madigan noted that almost immediately after the result of the UK referendum was known, members of the E.U.27 met in Bratislava, where they recognized that "the E.U. is not perfect but it is the best instrument we have for addressing the new challenges we are facing."
Looking forward, Madigan said the future of the E.U. "is inseparable from the future of the world," and that as such, members must adapt to the new challenges faced not only on the continent, but throughout the world.
Europe is and must be "much more than a debate on institutions," she said. Rather, "it is about achieving outcomes for all our citizens and the expression of our values in the world."
Voicing his hopes for the outcome of the conference, Habsburg said his biggest desire is that "we should not talk so much about each other, but talk with each other, and most of all listen to each other."
"I have the impression that some countries which are at times being perceived as being very critical of Europe or even rebellious, often only have wishes that could somehow also further the common European cause, but are often not listened to or are often drowned in lots of political narratives," he said.
However, during the conference everyone will be able to speak up about their own ideas and visions of Europe, he said, explaining that discussion groups will focus largely on questions such as "what is your idea about the path of Europe in your part of the world? What are you dreams? Where could we go? What do we have in common?"
"It's a real serious stopping, sitting down together and talking, and I think Europe really needs that now," he said. And while heads of state meet with regularity, the conference is unique in that so many people from different levels of both Church and state will attend and share ideas.
"So it's really going to be a very interesting experience," he said. "I think this conference is an incredible sign of hope."
Hannah Brockhaus contributed to this report.