Black smoke rose from the chimney atop the Sistine Chapel on Wednesday, signaling that the first round of voting in the papal conclave failed to elect a new pope.

Continuing a centuries-old tradition, 133 cardinal electors gathered at the Vatican to begin the process of selecting the 267th head of the Catholic Church, following the death of Pope Francis last month.

The day commenced with a solemn mass at St. Peter's Basilica, celebrated by Cardinal Giovanni Battista Re, who also presided over the 2013 conclave that elected Francis.

Afterward, the cardinal electors convened in the Pauline Chapel and processed into the Sistine Chapel, where the conclave is taking place.

The Sistine Chapel, adorned with Michelangelo's iconic frescoes, remains sealed off from the outside world until a new pope is chosen.

Under the conclave's rules, a two-thirds majority is required to elect the next pontiff.

This year's conclave continues a tradition dating back to 1492, when the Sistine Chapel hosted its first papal election—the same year Christopher Columbus reached the Americas.

While the papal selection process once stretched on for years, as in the mid-1200s, more recent elections have moved swiftly. In 2013, Francis was elected after five ballots over two days.

Pope Francis passed away on April 21 at the age of 88, following a series of health complications, including cardiac arrest.

The conclave will resume voting on Thursday as the Church awaits the emergence of its next leader.

If a new pope is elected, white smoke will billow out of the chimney and the formula "habemus papam" (Latin for "we have a pope") will be pronounced by the cardinal protodeacon from the balcony of St. Peter’s Basilica.