Complex sentence: During the early 1900s, the Cowichan Valley attracted many settlers from the Commonwealth and Eastern Canada, many of these settlers were alumni from traditional British public schools, and wished to have a similar education for their sons.
Split into simpler sentences: During the early 1900s, the Cowichan Valley attracted many settlers from the British Empire and Eastern Canada. Many of these settlers had attended traditional British public schools, and wished to have a similar education for their sons.