VATICAN CITY — Pope Francis will be offering several hundred poor people — homeless, migrants, unemployed — a lunch of gnocchi, veal and tiramisu when he celebrates his first World Day of the Poor in the spirit of his namesake, St. Francis of Assisi.

Francis begins the events Sunday with a Mass for an estimated 4,000 people in St. Peter's Basilica. Afterward, about 1,200 will join him for lunch in the Vatican's audience hall, where they'll be serenaded by the Vatican gendarmes' band and a children's choir. The rest will have lunch at nearby pontifical colleges.

Giuseppe Capurso, a homeless man from Bari, says he'll be there for the event, even if he doesn't expect much.

"I am like in a tunnel, where I can never see the light at the end," he said from the small room he shares at the St. Giacinta homeless shelter.

Francis has championed the plight of the poor, saying in one of his first public encounters after his 2013 election that he wanted a "church that is poor and for the poor." He has built showers, a barber shop and laundry for the homeless who live around the Vatican, and on his birthday has invited a few to join him for cake.

On Thursday, the Argentine Jesuit made a surprise outing outside the Vatican walls to visit the makeshift health clinic set up for the week leading up to Sunday's Mass that is offering free visits with cardiologists, dermatologists, gynecologists and experts in infective diseases. The Vatican called it a "field hospital" — the term Francis himself has used to describe the church he wants: one that welcomes in the poor and wounded and gives them merciful aid.

In a letter announcing the day celebrating the poor, Francis called his namesake "an outstanding example" of how deeds, and not just empty words, are needed to address the challenges posed by poverty. St. Francis was the 12th-century founder of the Franciscan religious order who renounced his wealth to live as a beggar.

"Tragically in our own time, even as ostentatious wealth accumulates in the hands of a privileged few — often in connection with illegal activities and the appalling exploitation of human dignity — there is a scandalous growth of poverty in broad sectors of society throughout the world," the pope said.