it tells us:

"The Bulgarian heard of me, the Great Knez Desimir of Moravia, Radivoi Knez of Preslav and all of the Knez bulgarian gethered together around Solun, and fought for the great blood and talked: send us a one of ours. So they sent me. The Bulgarians received me celebrant and brougth me in the town Ravn on the river Bregalnica. I wrote them their letter(characters). I teached them, and many of them converted on their own. They swore to give the Pravoslav Faith of Christ further. "(free translation)

It is from the book:
(Й. Иванов, "Български старини из Македония", БАН, 1970 г. ).'
Online Link for the Solun Legend

Info about Moravia:
http://en.wikipedia.org/wiki/Moravia

500 русских фамилий булгаро-татарского происхождения

500 Russian families of Bulgarian- Tatar descent.