Catholic bishops approved a proposal Saturday allowing some married men to be ordained as priests in the Amazon region.

The proposal, which must be approved by Pope Francis, would be a historic change to the church's centuries-old tradition of unmarried priests. It passed by a vote of 128-41 and applies only to some churches in the Amazon region that are experiencing a shortage of priests. The region includes parts of Bolivia, Brazil, Colombia, Ecuador, French Guiana, Guyana, Peru, Suriname and Venezuela.

The proposal, known as "viri probati," refers to older Catholic men, who have stable families, are respected in their communities and who are already ordained as deacons in the church.

Allowing married men to become priests is not the same thing as allowing priests to marry, so the change would not affect the rule of celibacy for Catholic priests, who are not allowed to marry.

Pope Francis must approve the proposal for it go into effect, something he said he hopes to respond to by the end of the year. The pope has previously stated he was open to studying the possibility of allowing married men to be ordained.

Although the Catholic Church currently only ordains unmarried men to the priesthood, some converts, from Anglicanism for example, can become Catholic priests even if they are already married.

The proposal to ordain married men was one of the most contentious recommendations voted on Saturday evening at the conclusion of a three-week-long meeting at the Vatican to discuss environmental and religious issues affecting the Amazon region.

The Vatican invited 184 bishops and priest from the Amazon region and around the world for the special meeting known as a synod. Thirty-five women, mostly religious sisters and nuns, were invited but did not have voting rights.

Another proposal recommended continuing to study the possibility of ordaining women as deacons. A commission set up by Francis in 2016 did not result in any conclusive recommendations.