In historical articles, the past tense is strongly preferred. While history can be written in the present tense, the general audience of Wikipedia will usually expect the past tense on historical subjects and events. The present tense in English is only correctly used to describe past events in a work of fiction. This is referred to as the "historical past tense".
Remain as objective as possible. The point and ideal of Wikipedia is to create an neutral encyclopedic body of knowledge. Avoid using the first-person point of view (emphasizing the facts; not the editor). Explain the evidence (from the links and references) and explain the reasons of any conclusions.