My Dad pointed me in the direction of David Weber's "Safehold" series, and I'm on book 5 already, as I can't put my Kindle down!
Imagine a re-working of the development of the Royal Navy and British industrialisation & expansion, but set against the backdrop of a religious schism and holy war, among the surviving final enclave of humanity, driven into hiding by a ruthless alien enemy...
...yes, I know it sounds complicated, but it really is quite brilliant!