Upvote:3
The Anglo-Saxon kingdoms form in Britain in the early 6th century, which is 150 years after the fall of the Roman Empire. During this period:
Anglo-Saxon law was written in the vernacular and was relatively free of the Roman influence found in continental laws that were written in Latin. Roman influence on Anglo-Saxon law was indirect and exerted primarily through the church. There was a definite Scandinavian influence upon Anglo-Saxon law as a result of the Viking invasions of the 8th and 9th centuries. Only with the Norman Conquest did Roman law, as embodied in Frankish law, make its influence felt on the laws of England.
So Roman tradition is the wrong place to look for the customs and legalities of manumission in the second half of the first millenium C.E. The original Germanic traditions of the invading (and ruling) Anglo-Saxons would have slowly melded with Scandinavian influences of the Vikings from the 8th Century on. The formalized traditions and records of English Common Law can be traced to the Norman Conquest.
My answer to the question "How were laws promulgated in the Middle Ages?" provides additional links to Description and History of Common Law and an academic paper on The Jury and the English Law of Homicide 1200-1600.
I don't have time just now to do more than peruse them quickly, but here is a casual descriptions of slavery in Anglo Saxon England and a more academic introduction to The Church and Slavery in Anglo-Saxon England.