Background
BM 124571 (Ninurta chasing Anzu) is an alabaster (gypsum) stone relief featuring a critical scene of the Epic of Anzu prestige myth. In the relief, currently at The British Museum, Ninurta is chasing the eagle-lion monster named Anzu because he had stolen the Tablet of Destinies. The British Museum describes the well-preserved artifact as Anzu and Ninurta:
"Gypsum wall panel relief: showing the monster Anzu facing left. The panel is part of a group as follows: gypsum wall panel reliefs showing god and monster. The god is Ninurta, chief god of the city of Nimrud and has a thunderbolt in each hand; he pursues the monster Anzu. The panel is inscribed with cuneiform script."
Indeed, the detailed artifact shows what looks like a dragon, perhaps the first one in recorded history. The artifact was discovered in Kalhu, modern-day northern Iraq, by Austen Layard in 1853 and dates back to the Assyrian empire under Ashurnasirpal II, a notable king of ancient Assyria. The Anzu bird, pictured prominently, looks like a dragon and its symbol dates back to the Sumerian empire of 3000-1900 BCE. It was discovered at the Temple of Ninurta, an important shrine to Ninurta.
Discovery and acquisition
This artifact was acquired by the British Museum in 1851. The images of BM 124571 were first published as plate number 5 in 1853 by Austen Henry Layard (M.P.). The initial sketches were so detailed that they remain in popular use today. The Anzu bird was originally reserved for the Assyrian empire but was discovered to be a prominent part of the Sumerian empire as well. Stephanie Dalley, a notable Sumerian and Babylonian translator, noted that there are two primary versions of the myth: the Old Babylonian (OB, 2nd millennium BCE) and Standard Babylonian (SB, 1st millennium BCE) versions. Alternatively, Jeremy Black and Anthony Green suggest in an iconography caption that the bird-figure may be Anzu or Asakku.
Relation to Babylonian mythology
This inscription may apply to two separate myths about Anzu and Ninurta. It may apply to the Epic of Anzu, in which Ninurta tracks down Anzu to recover the tablet of destinies. It may also be in relation to Ninurta and the Turtle.
https://books.google.com/books?id=U4mFAgAAQBAJ&pg=PA44&lpg=PA44&dq=ninurta+attacks+anzu+bird&source=bl&ots=e2mhM9eL5z&sig=ACfU3U0A1SJYKvq2usR_sX6Or6c8PMBoaA&hl=en&sa=X&ved=2ahUKEwjO9baAi97iAhVUwcQHHZRWAzA4ChDoATAEegQICRAB#v=onepage&q=ninurta%20attacks%20anzu%20bird&f=false