Complex sentence: St. Barbe Baker's father wanted him to enter the ministry, so at 13 he was sent to Dean Close School, a boarding school in Cheltenham, where he became interested in the sciences of botany and forestry.
Split into simpler sentences: St. Barbe Baker's father wanted him to enter the ministry. At 13, he was sent to Dean Close School, a boarding school in Cheltenham, where he became interested in the sciences of botany and forestry.