|First page of the Textus Roffensis.|
The water damage is from the early 1700s.
What makes it so special? The subject matter, partly. The first manuscript that comprises the Textus Roffensis is is a copy of the laws during the reign of Æthelbert. By creating this record, we have the earliest known example of an (Old) English document,* since the laws of Æthelbert were assembled by 604. And the English is rare: most Anglo-Saxon documents are in the dominant West Saxon dialect, but the Textus is in the Jutish dialect of Anglo-Saxon.
Æthelbert's laws were referenced by Alfred the Great when he created his own laws, and were mentioned by Bede. The Textus was clearly only one of a number of manuscripts that existed to carry these laws to others.
The Textus also has laws from Æthelbert's successors. Wihtred of Kent (reigned c.690 - 725), who died on 23 April 725, created many laws that gave rights to the Church. For example, the Church was free from taxation, and a bishop's word was considered as good as a king's oath.
One of the reasons the Textus Roffensis is prized by English historians is that its attempt to bring together several of the laws of kings in one document:
represents a new self-conscious attempt at recording an English heritage, after the Norman Conquest. The incomers needed an effective guide to the law of King Edward (i.e. King Edward the Confessor) as the Conqueror and King Henry his son promised to observe it; incomer and native alike needed all the resources of the book to preserve their ancient rights and recent acquisitions. [source]Compiled as it was in the 1120s, the Textus Roffensis is seen as a reminder to the Norman rulers of what rights and privileges were held prior to the Norman Invasion that they were promised would be respected.
*Technically, it also qualifies as the earliest example of a Germanic language document, so no other German-language records exist from the early 7th century.