Thousands of people are expected to gather in St. Peter’s Basilica in the Vatican on Wednesday evening to attend what will likely be Pope Benedict’s final public mass before leaving office.

The Ash Wednesday Mass was originally scheduled to have taken place in a small church in Rome but was then moved to St. Peter’s Basilica so that more people could attend.

Ash Wednesday marks the beginning of the Lenten season of sacrifice in the Catholic Church.  During services, the faithful queue up to have their foreheads marked with ash crosses symbolising penitence and mortality.

Lent is the 40-day period leading up to Easter, representing the 40 days Jesus spent fasting in the desert.

Ash Wednesday and Lent is observed by Roman Catholics, Lutherans, Methodists, Presbyterians and Anglicans.

People could be seen queuing to enter the Vatican by early afternoon for their chance to get a glimpse of the pontiff before he resigned on Feb. 28.

Pope Benedict, in his first public comments since he announced that he would become the first pontiff in centuries to resign, said he was fully aware of the gravity of his decision but confident that it would not hurt the Church.

Speaking at his weekly general audience, the pope, who looked and sounded strong, was interrupted several times by   thunderous applause from the some 8,000 faithful and tourists who packed the vast audience hall.

But experts say the transition period for a newly elected pope may not be easy.

The Vatican said on Wednesday that the conclave to decide the successor to Pope Benedict will start as early as March 15.

With files from 680News