The Protestant march passes through a mainly Catholic area . Trouble flared in Ardoyne and other areas of Belfast last month after a decision to allow another Protestant parade to pass through a mainly Catholic neighborhood on July 12 , a day when Protestants march to celebrate the victory of England 's King William III over his ousted Catholic predecessor , James II , in 1689 . Saturday 's march is the largest by the local Scout group . Smaller events are also taking place elsewhere today .
The Protestant march passes through a mainly Catholic area . Saturday 's march is the largest by the local Scout group . Smaller events are also taking place elsewhere today .