Complex sentence: Christians formed a majority of Lebanon's population before the Lebanese Civil War, but now are believed to form a large minority; however, if one counts the estimated 9--14 million strong Lebanese diaspora, they form far more than the majority of the population.
Split into simpler sentences: Christians formed a majority of Lebanon's population before the Lebanese Civil War, but now are believed to form a large minority. However, if one counts the estimated 9--14-million-strong Lebanese diaspora, they form far more than the majority of the population.