Jeapes, Ben. The New World Order
Divergence: 1645 CE
What if: The English Civil War was disrupted by introduction of rapid fire weapons, and then arrival of a crosstime invading force.
Summary: Near-human "Holekhor" arrive on Earth through a "gate" in Berkshire and become involved in the English Civil War, supporting the royalist cause and then carving out an enclave of their own. Six years later, relations are endangered by Holekhor priests unimpressed by the Englishmen's single god.
Published: Random House UK/David Fickling 2004 (0385606869), 2005 (0385750137BUY, 0385750153), Laurel Leaf 2006 (0553494910BUY), Corgi 2006 (0552550965).