The most important archaeological discoveries in Sumer are a large number of tablets written in cuneiform. Sumerian writing, while proven to be not the oldest example of writing on earth, is considered to be a great milestone in the development of man's ability to not only create historical records but also in creating pieces of literature both in the form of poetic epics and stories as well as prayers and laws. Although pictures — that is, hieroglyphs — were first used, cuneiform and then Ideograms (where symbols were made to represent ideas) soon followed. Triangular or wedge-shaped reeds were used to write on moist clay. A large body of hundreds of thousands of texts in the Sumerian language have survived, such as personal or business letters, receipts, lexical lists, laws, hymns, prayers, stories, daily records, and even libraries full of clay tablets. Monumental inscriptions and texts on different objects like statues or bricks are also very common. Many texts survive in multiple copies because they were repeatedly transcribed by scribes-in-training. Sumerian continued to be the language of religion and law in Mesopotamia long after Semitic speakers had become dominant.