A pioneer of television evangelism, Oral Roberts, has died at Newport Beach in California aged 91. He founded his own ministry and his own university, funded by millions he raised from supporters.

His oratorical skills were honed by travelling around the United States with a huge mobile tent in the style of an earlier generation of frontier preachers.

He regularly spoke of visions and commands from God. In 1987 he issued what some interpreted as an ultimatum to sympathisers to donate $8m or he would die – as he put it, God would "call me home". It worked: he raised more than $9m.

The evangelist's latter years were marred by scandal, most revolving round his son, Richard, who inherited his mantle and was at his bedside yesterday, after Roberts had a fall at the weekend and caught pneumonia leading to his death.

Roberts was born a minister's son in Oklahoma. After leaving university without a degree, he embarked on crusades with a tent holding up to 3,000. As his reputation grew, he left the Pentecostals to establish the Oral Roberts Evangelistic Association. He made his TV debut in 1955, and attracted a vast following. In 1963, he set up the Oral Roberts University in Oklahoma, which forbade students to drink, smoke or have sex before marriage.