Pope John Paul II's relations with the Eastern Orthodox Church were marked by a significant improvement in relations between Roman Catholicism and Eastern Orthodoxy.
Romania
In May 1999, Pope John Paul II visited Romania on the invitation from Patriarch Teoctist of the Romanian Orthodox Church. This was the first time a Pope had visited a predominantly Eastern Orthodox country since the East-West Schism in 1054, the event that separated Eastern Orthodoxy and Western Catholicism. On his arrival, the Patriarch and the President of Romania, Emil Constantinescu, greeted the Pope. The Patriarch stated, "The second millennium of Christian history began with a painful wounding of the unity of the Church; the end of this millennium has seen a real commitment to restoring Christian unity."
On 9 May, the Pope and the Patriarch each attended a worship service conducted by the other (an Orthodox Liturgy and a Catholic Mass, respectively). A crowd of hundreds of thousands of people turned up to attend the worship services, which were held in the open air. The Pope told the crowd, "I am here among you pushed only by the desire of authentic unity. Not long ago it was unthinkable that the bishop of Rome could visit his brothers and sisters in the faith who live in Romania. Today, after a long winter of suffering and persecution, we can finally exchange the kiss of peace and together praise the Lord." A large part of Romania's Orthodox population has shown itself warm to the idea of Christian reunification.
Greece
During his 2001 travels, John Paul II became the first Pope to visit Greece in 1291 years.
In Athens, the Pope met with Archbishop Christodoulos, the head of the Church of Greece. This visit has had a great influence on society of Ukraine. The Pope spoke to leaders of the All-Ukrainian Council of Churches and Religious Organisations, pleading for "open, tolerant and honest dialogue".
Belarus
Catholics in Belarus (at least 10-15% of the population) had hoped for the Pope to visit their country, a trip he himself wished to make. Resistance from the Russian Orthodox Church and Belarusian President Alexander Lukashenko, however, meant the visit never happened.
Poland
Pope's relation with Polish Autocephalous Orthodox Church was marked by a series of hostilities. Pope supported Solidarity and catholic option while Polish United Workers' Party pursued russian model with Orthodox Church being marginalized but the only official state religion. Official Party's documents clearly stated that Catholicism should be embraced, extended, and extinguished in favour of Orthodox Church.
Russia
The Pope had also been saying during his entire pontificate that one of his greatest dreams was to visit Russia, but this never occurred. He had made several attempts to solve the problems which arose over a period of centuries between the Roman Catholic and Russian Orthodox churches, like giving back the Kazan icon of the Mother of God in August 2004. However, the Orthodox side was not enthusiastic, making statements like: "The question of the visit of the Pope in Russia is not connected by the journalists with the problems between the Churches, which are now unreal to solve, but with giving back one of many sacred things, which were illegally stolen from Russia." (Vsevolod Chaplin).