Question

Which is the most effective way to combine sentences 1 and 2? Alfred I, who ruled England, did it from A.D. 871 to 899, nearly 20 years. Alfred I ruled England for nearly 20 years, which were A.D. 871 to 899. Alfred I ruled England for nearly 20 years, from A.D. 871 to 899. Alfred I ruled England for nearly 20 years, and he ruled from A.D. 871 to 899.

Answer 1

Alfred I ruled England for nearly 20 years, from A.D. 871 to 899

i think it is right, let me know if im wrong 

Answer 2

The answer to your question would be that the most effective way to combine sentences 1 and 2 is the following one: Alfred I ruled England for nearly 20 years, from A.D. 871 to 899.

This is the best revision of the original sentence because it is idiomatic and therefore it reads fluently without sounding strange or odd.