Complex sentence: A star fort, or "trace italienne", is a fortification in the style that evolved during the age of gunpowder, when the cannon came to dominate the battlefield, and was first seen in the mid- 15th century in Italy.
Split into simpler sentences: A star fort, or "trace italienne", is a fortification in an style that evolved during the age of gunpowder when the cannon came to dominate the battlefield. It was first seen in the mid- 15th century in Italy.