He had participated in 16 under-age marriages and had 22 wives himself. He even married off 11 of his own daughters and two of his granddaughters to 'the prophet'

A rural West Texas jury handed ex-bishop Fredrick Merril Jessop the maximum prison sentence of 10 years, after finding him guilty of marrying polygamist leader Warren Jeffs to a 12-year-old girl.

Jeffs, 55, leader of a breakaway Mormon sect, is serving a life term for sexually assaulting two child brides.

The jury found Jessop, 75, guilty of performing an illegal marriage ceremony, a third-degree felony punishable by two to 10 years in prison and a fine up to $10,000.

Jeffs' polygamist sect, the Fundamentalist Church of Jesus Christ of Latter Day Saints, which experts estimate has 10,000 followers in North America, has been condemned by the mainstream Mormon Church and is accused of promoting marriages between older men and girls.

In the sentencing phase of the trial, state prosecutors said Jessop had married 11 of his daughters and two of his granddaughters to Jeffs, the sect's lone prophet, who reportedly excommunicated Jessop from the church in January.

Lead prosecutor Angela Goodwin also presented evidence showing Jessop had participated in 16 underage marriages and had 22 wives himself.

"What do we do with a man who has put in harm's way so many people, who worked as some twisted Pez dispenser, popping off daughters for the prophet?" Goodwin said on Tuesday, arguing for the maximum sentence.

Jessop's attorney, Rae Lefeiste, argued that a 10-year sentence was too long for a 75-year-old man and pointed out that the state law his client was found guilty of violating was relatively new, having been added to the books in September 2005.

The FLDS, which broke off from the mainstream Mormon church in the early 20th century, believe polygamy is necessary to advance to the highest level of heaven. FLDS men enter into so-called "celestial marriages" with multiple wives in a process known as "sealing."

Jessop is one of 11 FLDS men the state of Texas has sought to prosecute after Texas Rangers unearthed a trove of documents from a vault during an April 2008 raid on the sect's West Texas ranch near Eldorado.

Ten of the men have been prosecuted and convicted of crimes including bigamy and sexual assault of a child.

Jessop, then a bishop in the church, was in charge of running the ranch at the time of the raid. State prosecutors said the marriage ceremony that was the crux of his conviction had taken place on the ranch in 2006.