Cardinals will meet Tuesday to decide the date for Pope Francis鈥檚 funeral, starting a process that will culminate in the election of a new Catholic leader within three weeks.
Francis, the head of the world鈥檚 1.4 billion Catholics, died at his home in the Vatican on Monday aged 88 after suffering a stroke.
He had been recovering from double pneumonia that saw him hospitalised for five weeks.
Tributes have poured in from around the globe for Francis, a liberal reformer who took over following the resignation of German theologian Benedict XVI in 2013.
The Argentine pontiff鈥檚 home country prepared for a week of national mourning while India began three days of state mourning on Tuesday, a rare honour for a foreign religious leader in the world鈥檚 most populous nation.
Heads of state and royalty are expected for his funeral, due to be held at St Peter鈥檚 Basilica, with Donald Trump the first to announce he would attend.
鈥楬e was a good man, he worked hard and loved the world,鈥� the United States president said, despite the pontiff鈥檚 criticisms of his migrant deportation programme.
The funeral should be held between the fourth and sixth days after the pope鈥檚 death, according to the Apostolic Constitution 鈥� so between Friday and Sunday this week.
But the details will be decided by the cardinals, who have been summoned for a first of a series of 鈥榞eneral congregations鈥� starting at 9:00am.
Cardinals of all ages are invited to the congregations, although only those under the age of 80 are eligible to vote for a new pope in the conclave.
The conclave should begin no less than 15 and no more than 20 days after the death of the pope.
The pope鈥檚 body was moved into the Santa Marta chapel on Monday evening, and his apartment was formally sealed, the Vatican said.
His remains are expected to be transferred from the Santa Marta residence, where he lived and died, to St Peter鈥檚 Basilica starting Wednesday to lie in state.
Francis, who wore plain robes and eschewed the luxury of his predecessors, has opted for a simple tomb, unadorned except for his name in Latin 鈥� Franciscus, according to his will released Monday.
He will be buried in Rome鈥檚 Santa Maria Maggiore basilica, becoming the first pope in more than 100 years to be laid to rest outside the Vatican.
His death certificate released by the Vatican said Francis died of a stroke, causing a coma and 鈥榠rreversible鈥� heart failure.
He had been discharged from Rome鈥檚 Gemelli hospital on March 23, ordered to spend at least two months resting.
But Francis delighted in being among his flock and made numerous public appearances in recent days.
He appeared exhausted on Sunday during the Easter celebrations, but nevertheless greeted the crowds in his popemobile in St Peter鈥檚 Square.
Argentine football great Lionel Messi hailed his compatriot 鈥� himself a huge fan of the beautiful game 鈥� for 鈥榤aking the world a better place鈥�.
On Monday evening, thousands of faithful, some bringing flowers or candles, flocked to St Peter鈥檚 Square at sunset to pray for Francis.
He 鈥榯ried to get people to understand it doesn鈥檛 matter your sexual orientation, your race, it doesn鈥檛 matter in the eyes of God鈥�, Mateo Rey, 22, a Mexican student, told AFP.
鈥業 think that鈥檚 the closest to what Jesus intended.鈥�
Born Jorge Bergoglio, Francis was the first pope from the Americas and the first Jesuit to lead the worldwide Catholic Church.
An energetic reformer, he sought to open the Church to everyone and was hugely popular 鈥� but his views also sparked fierce internal opposition.
In 12 years as pope, Francis advocated tirelessly for the defence of migrants, the environment, and social justice without questioning the Church鈥檚 positions on abortion or priestly celibacy.
A fierce opponent of the arms trade, the former archbishop of Buenos Aires repeatedly called for peace in conflicts from Sudan to Gaza and Ukraine 鈥� although his pleas fell largely on deaf ears.
Outspoken and stubborn, Francis also sought to reform the governance of the Holy See and expand the role of women and lay people, and to clean up the Vatican鈥檚 murky finances.
Faced with revelations of widespread child sex abuse in the Church, he lifted pontifical secrecy and forced religious and lay people to report cases to their superiors.
However, victims鈥� groups said he did not go far enough.
