Complex sentence: About the same time the local horse of Durham and Northumberland were put into the field by Parliamentarian Sir Arthur Hesilrige, governor of Newcastle, and under the command of Colonel Robert Lilburne won a considerable success (30 June) at the River Coquet.
Split into simpler sentences: About the same time, the local horse of Durham and Northumberland were put into the field for the Parliamentarians by Sir Arthur Hesilrige, governor of Newcastle. On 30 June, under the direct command of Colonel Robert Lilburne, these mounted forces won a considerable success at the River Coquet.