Sentences of a paragraph are given below. While the first and the last sentences (S1 and S6) are in the correct order, the sentences in between are jumbled up. Arrange the sentences in the correct order to form a meaningful and coherent paragraph. S1: The demise of castles can ultimately be attributed to gunpowder. P: But the first gunpowder weapons were unreliable, inaccurate, and weak by standards. Q: This greatly undermined the military role of castles. R: During the 15th century, artillery became powerful enough to break through stone walls. S: Gunpowder was first introduced to Europe during the 14th century. S6: Castles were then replaced by artillery forts that had no role in civil administration.