Complex sentence: This fostered the growth of Pillau into an important port of the Duchy of Prussia, and a blockhouse was constructed in 1537, followed by a system of storehouses in 1543, and the earliest fortifications in 1550.
Split into simpler sentences: This fostered the growth of Pillau into an important port of the Duchy of Prussia. A blockhouse was constructed in 1537, followed by a system of storehouses in 1543 and the earliest fortifications in 1550.