Pueros latest story, Byzantines β (
http://www.eunuch.org/Alpha/B/ea_195130byzantin.htm), is a remarkable work of historical fiction. While I am not an expert in Byzantine history, I read enough of it as a hobby to know that the basic historical data in this story is entirely accurate. Having spent a day with Pueros as he expertly guided me through the remains of the largest Roman encampment in Britain (as well as several pubs), I would expect that the historical part of the story is 100% accurate.
I would only like to add one additional historical bit to his wonderful work. In Chapter μ The Export he begins with the quotation:
A well-known article of export [in al-Andalus] is slaves; boys and girls who have been taken from France and Galicia, as well as Slavic eunuchs. All of the Slavic eunuchs found on the face of the Earth come from Spain. They suffer castration in that country. The operation is done by Jewish merchants.
So wrote Ibn Hawqal, a 10th century Arabic chronicler, about trade from al-Andalus in what was then Moorish Spain. He was, of course, mistaken because many, albeit not all, Slavic eunuchs were created in Verdun. However, his error is understandable because all subsequently found themselves in Spain.
To this I would add a quotation from a 12th century grammarian, Ibn Hisham, who was concerned about misuse of the Arabic language word al-Saqlabi (person of Slavic origin). People use the word al-Saqlabi only to mean eunuch, whether he is a white or black. But his word should be related with the word al-Saqaliba, that is a group of Europeans. Its singular form is al-Saqlabi whether he is a eunuch or not. For blacks the word should not be applied, though most Saqaliba are eunuchs and for that reason non-Saqaliba eunuchs are also called by this name.
In other words, such a high percentage of Slavic slaves were eunuchs that the word Slav came to mean eunuch in popular Arabic. The word slave in English is also derived from Slav as the pagan Slavic lands of Eastern Europe were the origin of such a high percentage of western European slaves.