Complex sentence: The News Letter has historically been a hardline Unionist title, however when it was purchased by the Mirror Group in the 1990s Montgomery, then still with MGN, moved it to a more pro-peace process position.
Split into simpler sentences: The News Letter has historically been a hardline Unionist title. However when it was purchased by the Mirror Group in the 1990s Montgomery moved it to a more pro-peace process position.