(CNN) -- Evangelist Oral Roberts, founder of the Oral Roberts Evangelistic Association and Oral Roberts University, died Tuesday from complications of pneumonia in Newport Beach, California, his spokeswoman said. He was 91.

Roberts' son, Richard, and daughter Roberta were at his side, spokeswoman Melany Ethridge said in a statement.

Roberts was hospitalized Monday following a fall on Saturday, in which he suffered broken bones, Ethridge said earlier, adding he was being treated for pneumonia.

There will be a private interment, the statement said. Arrangements for a public memorial service in Tulsa, Oklahoma, are pending.

"Oral Roberts was a man of God, and a great friend in ministry," the Rev. Billy Graham said in a statement Tuesday. "I loved him as a brother. We had many quiet conversations over the years."

Granville Oral Roberts was born into poverty in Bebee, Oklahoma, on January 24, 1918, according to a brief biography released by Ethridge. His Christian ministry began with what he described as his own miracle healing of tuberculosis at age 17.

Roberts pastored churches in Oklahoma and Georgia and preached at revivals around the country while studying at Oklahoma Baptist University and Phillips University in Oklahoma, according to the biography.

In 1947, he founded the Oral Roberts Evangelistic Association in Tulsa, "and began conducting crusades across America and around the world, attracting crowds of thousands -- many who were sick and dying and in search of healing," the biography said. "Through the years, he conducted more than 300 crusades on six continents" and "laid hands" on an estimated 2 million people, according to association officials.

In 1954, he brought television cameras into services, providing what he liked to call a "front-row seat to miracles" to viewers, the biography said. He later began a television program, initially called "Oral Roberts Presents." The ministry's daily program, now called "The Place for Miracles," can be seen on more than 100 television stations, multiple cable and satellite networks and the Internet, Ethridge said.

"If God had not in his sovereign will raised up the ministry of Oral Roberts, the entire charismatic movement might not have occurred," said Jack Hayford, president of the California-based International Church of the Foursquare Gospel, in the statement. "Oral shook the landscape with the inescapable reality and practicality of Jesus' whole ministry. His teaching and concepts were foundational to the renewal that swept through the whole church."

Roberts founded the Abundant Life Prayer Group in 1958 "to address the around-the-clock needs of those suffering and requesting prayer," according to the biography. Today, prayer partners at Abundant Life continue to receive calls 24 hours a day. The group has received more than 23 million phone calls for prayer, the biography said.

Oral Roberts University was founded in 1963, built on 500 acres in Tulsa and dedicated four years later by Graham, according to the biography. Graduate schools including medicine, nursing, dentistry, law, education and theology were later added. Roberts served as school president until 1993 but remained a chancellor until his death.

He remained involved in his evangelistic association as much as his health allowed, Ethridge said Monday. His son, Richard Roberts, currently serves as president.

In 1977, Roberts said he had a vision of a 900-foot-tall Jesus, who told him to found the City of Faith Medical and Research Center. The biography said the center was aimed at "merging the healing power of medicine and prayer."

In 1986, Roberts announced that God would "call him home" unless he raised $8 million to send medical missionaries from the center -- an announcement that was widely publicized. He wound up raising $9.1 million, but the center closed in 1989. However, the biography said, it left "a lasting impact on the understanding by many medical professionals of the importance of treating the whole person -- body, mind and spirit."

In addition, Roberts wrote more than 130 books, the biography said. "His book 'The Miracle of Seed Faith' has more than 8 million copies in circulation. This book's key principles -- God is your source, sow your seed out of your need, and expect a miracle harvest -- formed a fundamental part of Roberts' ministry and legacy," the biography said.

Before his death, Roberts said, "After I'm gone, others will have to judge how well I've obeyed God's command not to be an echo but to be a voice like Jesus," the statement said. "As far as my own conviction is concerned, I've tried to be that voice with every fiber of my being, regardless of the cost."

Responding to news of Roberts' death, Graham said Tuesday: "Just three weeks ago, I was privileged to talk to Oral on the telephone. During the short conversation, he said to me that he was near the end of his life's journey. I look forward to the day that I will see Oral and Evelyn Roberts again in heaven -- our eternal home."

Roberts wife, Evelyn, died in 2005 after the couple had been married more than 66 years. Roberts is survived by his son and daughter and their spouses, along with 12 grandchildren and several great-grandchildren, Ethridge said.