The Sistine Chapel chimney in the Vatican released a plume of black smoke around 9 p.m. on Wednesday, May 7, signaling that the first vote of the papal conclave ended without a decision on who will succeed Pope Francis.

ALSO READ: Election of new pope gets underway

The 133 cardinals had entered the chapel earlier in the day, chanting Veni Creator Spiritus, a traditional hymn invoking the Holy Spirit, before casting their ballots beneath Michelangelo’s Last Judgment to begin the process to elect the 267th Bishop of Rome and leader of the Roman Catholic Church.

ALSO READ: When to expect a new pope? A look at the shortest and longest conclaves

Due to a late start, only one round of voting (out of four possible for one day) was held on Wednesday. Black smoke signaled that during the highly secretive voting no candidate had got the necessary two-thirds majority.

On Thursday, May 8, the cardinals will return to the chapel at 10:30 a.m. Rome time, with up to four rounds of voting expected, two in the morning and two in the afternoon.

ALSO READ: When to expect a new pope? A look at the shortest and longest conclaves

They will remain sequestered at Casa Santa Marta, the Vatican’s guesthouse, where Pope Francis lived until his death on April 21. The cardinals are cut off from all outside communication to ensure the secrecy and sanctity of the process.

Though the duration of a conclave is unpredictable, recent precedent points to a swift decision. Both Pope Benedict XVI and Pope Francis were elected on the second day of voting.

Papal conclaves have generally been swifter over centuries.

The longest conclave in history lasted nearly three years, from April 1292 to July 1294. Cardinals were locked in a stalemate that finally saw the election of Pope Celestine V.

In more recent history, the longest conclave was in 1740. That vote, which resulted in the election of Pope Benedict XIV, lasted 182 days.