The Vatican announced Saturday that Pope Francis will sign the third encyclical of his pontificate in Assisi on Oct. 3.

The encyclical is entitled Fratelli tutti, which means “All Brothers” in Italian, and will focus on the theme of human fraternity and social friendship, according to the Holy See Press Office.

Pope Francis will offer a Mass at the tomb of St. Francis in Assisi privately at 3 p.m. before signing the encyclical on the day before St. Francis’ feast day.

Human fraternity has been an important theme for Pope Francis in recent years. In Abu Dhabi the pope signed “A Document on Human Fraternity for World Peace and Living Together” in Feb. 2019. Pope Francis’ message for his first World Day of Peace as pope in 2014 was “Fraternity, foundation and pathway for peace.”

Pope Francis’ previous encyclical, Laudato Si’, published in 2015, had a title taken from St. Francis of Assisi’s “Canticle of the Sun” prayer praising God for creation. Prior to that he published Lumen Fidei, an encyclical begun by Pope Benedict XVI.

The pope will return from Assisi to the Vatican on Oct. 3. The beatification of Carlo Acutis will take place in Assisi the following weekend, and the “Economy of Francis” economic summit is also scheduled to take place in Assisi in November.

“It is with great joy and in prayer that we welcome and await the private visit of Pope Francis. A stage that will highlight the importance and necessity of fraternity,” Fr. Mauro Gambetti, the custodian of the Sacred Convent of Assisi said Sept. 5.