Complex sentence: It was exhibited at the Royal Academy summer exhibition in 1822, where it was so popular that a rail was installed to protect it from the thronging crowds, the first time that a rail was needed at the Royal Academy exhibition.
Split into simpler sentences: It was exhibited at the Royal Academy summer exhibition in 1822, where it was so popular that a rail was installed to protect it from the thronging crowds. This was the first time that a rail was needed at the Royal Academy exhibition.