Complex sentence: Vaasi, the language of the Church of the Lawgiver, was of course the native tongue of the Hazlani, and the social order was at least as oppressive in Hazlan as in Nova Vaasa, preparing the ground for the reception of The Lawgiver's message.
Split into simpler sentences: Vaasi, the language of the Church of the Lawgiver, was of course the native tongue of the Hazlani. And the social order was at least as oppressive in Hazlan as in Nova Vaasa, preparing the ground for the reception of The Lawgiver's message.