Complex sentence: Rev Dr Thomas Guthrie (1780-1873) of Edinburgh was also an early promoter of free schooling for working class children; he started what appears to have been the first Scottish free school for the poor.
Split into simpler sentences: Rev Dr Thomas Guthrie (1780-1873) of Edinburgh, was also an early promoter of free education for working class children. He started what appears to have been the first Scottish free school for the poor.