The following is taken from Islamtoday.com, but I have taken the liberty of correcting some spelling errors and adding commments in double brackets:
Question: Can you kindly list some Islamic documents concerning either hadîth or Islamic Law, that are extant and that predate the Muwatta’ of Imam Mâlik?
Answered by Sheikh Muhammad al-Qannâs
The Companions of the Prophet (peace be upon him) used to collect all the sayings and actions of the Prophet (peace be upon him) and relate them among themselves and memorise them.
Some of the Companions used to keep written records during the era of the Prophet (peace be upon him). Writings from this time period include the document of Abû Bakr al-Siddîq regarding Zakâh, the document of `Ali b. Abî Tâlib discussing the age classifications of camels and something about injury compensation, and the document authored by `Abd Allah b. `Amr b, al-`Âs entitled al-Sahîfah al-Sâdiqah. Continue reading →