Complex sentence: The second attack, following their defeat at the Battle of New Orleans, was successful, took place in February 1815, after the Treaty of Ghent had been signed but before the news had reached that part of America.
Split into simpler sentences: The second attack, following their defeat at the Battle of New Orleans, was successful. However, it took place in February 1815, after the Treaty of Ghent had been signed but before the news had reached that part of America.