Complex sentence: He was assisted by Leiden church members John Carver and Chief Agent Robert Cushman in obtaining provisions (goods and supplies) both in England and in Leiden and enough food for the colony's sustenance for its first year.
Split into simpler sentences: He was assisted by Leiden church members John Carver and Chief Agent Robert Cushman, in obtaining provisions (goods and supplies) both in England and in Leiden. And enough food for the colony's sustenance for its first year.