Complex sentence: The first bearer of the title was Yongzhang (永璋; 1735--1760), the third son of the Qianlong Emperor, who was posthumously honoured with the title "Prince Xun of the Second Rank" by his father in 1760.
Split into simpler sentences: The first bearer of the title was Yongzhang (永璋; 1735--1760), the Qianlong Emperor's third son. Yongzhang was posthumously honoured with the title "Prince Xun of the Second Rank" by his father in 1760.