In 2015, Pope Francis established the "World Day of Prayer for the Care of Creation," to be celebrated annually on September 1.
This date was chosen to coincide with a day that Eastern Orthodox Christians already had on their liturgical calendar.
Pope Francis explains this in his letter that established this celebration in the Catholic Church.
In 1989, the late Ecumenical Patriarch Demetrios I, wrote a letter on the environment, marking the first annual “Day of Prayer for Creation" on September 1.
This day was chosen for a specific reason for Orthodox Christians. It is traditionally the first day of the new liturgical year in the Orthodox church.
According to the Orthodox Church in America, "Before the introduction of the Julian calendar, Rome began the New Year on September 1."
The beginning of a new year reflects the symbolism of new life as well as the themes of harvest, which commonly occurs in September in the Northern Hemisphere.
It also coincides with a day that has traditionally been associated with Jesus' entering the synagogue to announce his mission to preach the Gospel.
It is in this context that the World Day of Prayer for the Care of Creation was established in the Catholic Church.
