New Delhi: The Missionaries of Charity nuns sang hymns and offered special prayers on Tuesday after Pope Francis set the date for the canonization of Mother Teresa, their world renowned founder.

“We are very happy,” Sunita Kumar, a longtime friend, told reporters shortly after the Vatican announcement of the Sept. 4 canonization.

The nuns at the congregation’s headquarters in Kolkata broke into prayerful celebration as soon the Pope signed the decree on the canonization of Bless Teresa and four others in the Vatican.

Mother Teresa had adopted Kolkata, formerly known as Calcutta, as her home for nearly five decades of service to the poorest of the poor.

The canonization will take place at the Vatican, a day before the 19th anniversary of her death. But Kolkata has already started preparing with church-organized events for the woman known as the “saint of the gutters.”

The announcement “not only has brought smiles on our faces but also has given us another reason to live and bring meaning to our lives and the lives of others,” said Archbishop Thomas D’ Souza, who celebrated a special Mass. “Because Mother, as an icon of mercy, of service of God’s love and his presence among the poorest of poor, continues to give meaning to the lives of everyone.”

Teresa, born Agnes Gonxha Bojaxhiu in 1910 in what is now Skopje, Macedonia, joined the Loreto order of nuns in 1928 and said she was inspired to found the Missionaries of Charity while on a trip to Darjeeling in 1946.

The order has more than 4,000 members in 130 centers around the world. The nuns are recognizable by their signature plain white cotton sari with a blue border.

Pope John Paul II beatified Teresa in 2003, the third in the four stages of sainthood. In December, the Vatican announced that Teresa’s intervention in healing a Brazilian man suffering from a viral brain infection in 2008 has been declared miraculous — “inexplicable in the light of present-day medical knowledge.”