Complex sentence: The destruction of Ebla is mentioned in the fragmentary Hurro-Hittite legendary epic "Song of Release", discovered in 1983, and which Astour consider as describing the destruction of the second kingdom.
Split into simpler sentences: The destruction of Ebla is mentioned in the fragmentary Hurro-Hittite legendary epic "Song of Release", which was discovered in 1983. According to Astour, the "Song of Release" describe the destruction of the second kingdom.