Definition: Slavery is the social and legal designation of specific persons as property, for the purpose of providing labor and services for the owner without the right of the slave to refuse, or gain compensation.
This will be a general view of slavery in medieval Europe.
Concerning Slavery in Medieval Europe:
Many slaves were taken as a direct result of warfare and raiding; whilst others entered into a form of slavery as a means of repaying a financial obligation.
Throughout the medieval era, slaves were traded openly in most cities, including cities as diverse as Marseille, Dublin and Prague, and many were sold to buyers in the Middle East. The town of Caffa in the Crimea was called the capital of medieval slave trade.
The main slave-routes were through the profitable slave markets of the Crimea - many Slavonic peoples were sold through here. Following the conquest of North Africa and the Iberian Peninsula, the Muslim world became a huge importer of slaves from Eastern Europe. However, Muslims, due to religious constraints, were obliged to purchase their slave through Jewish traders.
In Scandinavia, slaves were referred to as thralls; in Russia they were called kholops; and in the feudal system, slaves became known as serfs.
William the Conqueror on Slavery c.1080:
Let Christians not be sold outside of the land or to heathens:
41. Also we forbid any one to sell a Christian into a foreign land and especially to heathens. For let great care be taken lest their souls for which Christ gave His life be sold into damnation.
Concerning serfs and their manumission:
15. And we prohibit any one to sell a man out of the country. But if he, who wishes to make his serf free, hand him over to the sheriff by his right hand in full assembly, he must proclaim him quit of the yoke of his servitude by manumission, and show him free ways and gates and give him arms, viz., lance and sword; finally the man is made free.
Source: "Ancient Laws and Institutes of England" by Benjamin Thorpe, ed (London: Eyre & Spottiswoode, 1840).
The Visigoth Code also has formulated laws with regards to slavery:
X. Where a Freeman Allows Himself to be Sold - Any freeman who permits himself to be sold, and shares the price with the vendor, and, afterwards, desiring to cheat the purchaser, publishes the fact for the sake of reclaiming his liberty, shall not be heard, but shall remain in slavery; for it is dishonorable that a freeman should voluntarily subject himself to servitude. But if he who sold himself, or permitted himself to be sold, should have sufficient property to redeem himself, or, if his parents should choose to give the price of his redemption to him who owns him; then the entire amount for which he was sold shall be returned to the purchaser, and the person who was the object of the sale shall regain his freedom.
XI. Concerning Free Men and Free Women Sold by Slaves or Freemen - If anyone should dare to sell or give away a freeborn son, the judge shall at once cause the offender to be arrested. And in order that the said freeborn person may be restored to his proper rank, the judge shall require the vendor of such person to pay a hundred solidi of gold; and if he should not have sufficient property to pay this sum, he shall receive a hundred lashes in public, and shall be delivered over as a slave to him whom he had the audacity to sell, or give away. If a slave should treat a freeborn person in this manner, after being arrested he shall receive two hundred lashes in public, by order of the judge, and having been scalped he shall be condemned to perpetual servitude This rule shall apply also to donations and sales of freeborn women.
XII. It shall be Illegal for Parents to Sell their Children, or, by any Contract whatsoever, to Place Them in the Power of Others - It shall not be lawful for parents to sell, give away, or pledge their children. And no one who purchases or receives a child under such circumstances, shall have any legal right to it whatever, but, on the other hand, he shall lose the price, or the amount advanced as a loan, which he paid to the parents of said child.
From the Anglo-Saxon Laws:
From the Laws of Ine of Wessex c.690.
Cap. 11. - If any one sell his own countryman, bond or free, though he be guilty, over sea, let him pay for him according to his 'wer' (The pecuniary estimation of a man, by which the value of his oath and the payment for his death were determined).
From the Laws of Edward the Elder (901 - 924AD):
Of him who forfeits his freedom - 9. If any one, through a charge of theft, forfeit his freedom, and deliver himself up, and his kindred forsake him, and he know not who shall make bot for him; let him then be worthy of the theow-work which thereto belongs, and let the wer abate for the kindred.
Gregory of Tours
Book III, Chapter 15: Many sons of senatorial families were thus given but when a new quarrel broke out between the kings they were reduced to servitude on the fiscal domains. And those who had taken care of them now made slaves of them. Nevertheless many escaped by flight and returned to their own country, others were kept in servitude ....
Fifth Council of Orleans 549AD:
Concerning Freedmen - whatever slaves be released from servitude by free masters, shall remain in that freedom which they then received from their lords.
"For my part, I adhere to the maxim of antiquity: The throne is a glorious sepulchre."