The Rev. Ralph D. Winter, a Presbyterian Church (U.S.A.) minister who pioneered frontier evangelism and was named one of America’s 25 most influential evangelicals by Time magazine in 2005, died May 20 at his home in Pasadena, CA after battling multiple myeloma and lymphoma. He was 84.

A native of South Pasadena, Winter earned an engineering degree from Cal Tech before serving in the U.S. Navy during World War II. After the war, he attended Cornell, Columbia and Princeton Theological Seminary before being ordained in 1956.

Winter began his career as a PC(USA) missionary in Guatemala, where he served for 10 years. He returned to the U.S. to become professor of missions at Fuller Theological Seminary, where in 1976 he left the classroom to found the U.S. Center for World Mission and a year later the William Carey International University.

Winter stepped onto the world stage in 1974 at the International Congress on World Evangelization in Lausanne, Switzerland, where he issued a call for Protestant missionaries to evangelize the world’s “unreached people” — those who had not been exposed to Christianity. In identifying mission fields, Winter looked for “ethnic pockets,” isolated areas where language, ethnicity, culture and social status as well as religion had hindered the spread of the gospel.

Winter is survived by his second wife, Barbara (his first wife of 50 years and fellow missionary, Roberta, died in 2001); daughters Elizabeth Gill, Rebecca Lewis, Linda Dorr and Patricia Johnson; 14 grandchildren; one great-grandchild; and two brothers, Paul, a structural engineer, and David, president of Westmont College in Santa Barbara.

A memorial service for Ralph Winter is scheduled on June 28 at Lake Avenue Congregational Church in Pasadena.