It is a known fact that the original balts mixed with the original slavs creating balto-slavs but is this the end all for what would be pure slavic blood? No and I'll explain why. Polish, Serbs and Croats have claim to Sarmatian roots in what is usually called non-slavic theories, meaning they were sarmatian tribes that were later slavicized, claiming they are not slavic. Slavic theories deny sarmatian roots. So which one is true?
If you use common sense and you look at the history of the slavic homeland (ukraine) you will see that our balto-slavic ancestors mixed with, conquered, were conquered by and absorbed the following tribes Cimmerians, Scythians and Sarmatians (including the alans). All were indo-european tribes from central asia speaking an iranian dialect.
You can see many historic maps proving these migrations and there disappearnces coinciding with the emergence of slavs in the area. I believe that what would be pure slavic is the common blood between all slavs. The original Slavs, Balts, Cimmerians, Scythians, Sarmatians and to a far lesser degree Goths are the ancestors of all slavs.
The scytho-sarmatian light cavalry tradition was preserved by serbs and the cossacks. Here is a video of the old serbian cavalry which later became the hussars of poland, if you know anything about the scythians/sarmatians you will know that is where this tradition came from. SERBIAN HUSSARS (https://www.youtube.com/watch?v=bZnNyt49Td8#) The traditional cossack clothing and cavalry also have undeniable scytho-sarmatian roots.
Also serbs and croats names come from old sarmatian tribes, sarboi (serb), harvaitii (hrvat), an old city named chroates (croat) and the fact that polish royalty claimed to be descendants of the sarmatian nobility.
You will also notice the carpathians referred to in ancient times as montes serrorum meaning serb mountains in what is modern day romania/ukraine in the same vicinity as the slavic homeland and the scythians/sarmatians.
Non scandinavian Germanics also absorbed some scythian/sarmatian blood as well in their migrations and the goths mingled with slavs also, if you look at the old maps you will see they border each other and if you look at several maps you'll see some overlap also.
The purest blood descendents of the sarmatians living today are abkhazians and ossetians in southern russia/north caucasus. If you saw them you might not be able to tell them apart from some slavs but I assure these people are not slavic. You can also see non slavic balts in lithuania/latvia who bear resemblences to us as well.
here is a map before they were absorbed by the balto-slavs
http://en.wikipedia.org/wiki/File:Scythia-Parthia_100_BC.png (http://en.wikipedia.org/wiki/File:Scythia-Parthia_100_BC.png)
http://www.celtiberia.net/imagftp/im298954897-sarmatians.gif (http://www.celtiberia.net/imagftp/im298954897-sarmatians.gif)
sarmatian gold
Sarmatian Gold (http://www.dailymotion.com/video/xb1g8o)
scythian art and gold
http://www.google.com/imgres?imgurl=http://warriorsofhistory.com/research/Scythian/Scythian%2520Gold%2520depicting%2520weapons%2520and%2520dress%2520of%2520Scythian%2520Warriors%25205th%2520cent%2520BC.jpg&imgrefurl=http://warriorsofhistory.com/research/Scythian/&h=296&w=476&sz=46&tbnid=y-10LZJ6gkqu8M:&tbnh=80&tbnw=129&prev=/images%3Fq%3Dscythian%2Bgold&hl=en&usg=__xNejBKAyKYNjkTW5T5m3UxKLhmQ=&ei=tqjoS624ApOStgOh3LDjBw&sa=X&oi=image_result&resnum=2&ct=image&ved=0CBkQ9QEwAQ (http://www.google.com/imgres?imgurl=http://warriorsofhistory.com/research/Scythian/Scythian%2520Gold%2520depicting%2520weapons%2520and%2520dress%2520of%2520Scythian%2520Warriors%25205th%2520cent%2520BC.jpg&imgrefurl=http://warriorsofhistory.com/research/Scythian/&h=296&w=476&sz=46&tbnid=y-10LZJ6gkqu8M:&tbnh=80&tbnw=129&prev=/images%3Fq%3Dscythian%2Bgold&hl=en&usg=__xNejBKAyKYNjkTW5T5m3UxKLhmQ=&ei=tqjoS624ApOStgOh3LDjBw&sa=X&oi=image_result&resnum=2&ct=image&ved=0CBkQ9QEwAQ)
before the scythians came the inhabitants there were called cimmerians who were later absorbed. not much is known about them
http://en.wikipedia.org/wiki/Cimmerians (http://en.wikipedia.org/wiki/Cimmerians)
hey are identified with the srubna and yamna cultures which were both indo-european
I forgot to mention the scytho-sarmatian connection between serbian and cossack warfare. The Scythians and Sarmatians were both horse riding nomadic warrior tribes. The sarmatians used both male and female warriors hence there comparison to the amazons by greek historians. The children of sarmatian warriors would be placed in a saddle on the day of their birth this is evidenced by them growing up with bowed legs because they had learned to ride in a saddle before they could walk. This is proven by anthropological evidence (bones). The horse was sacred to them. Slavs kept this tradition especially the cossacks but the goths did not as they used heavy cavalry instead of the light cavalry that the sarmatians, scythians and every other nomadic tribe to come across the steppes used (including asiatics like hunns, mongols, turks etc).
If any of you are interested in sarmatians or scythians I recommend osprey's men-at-arms series of books, it's complete with pictures and art, mostly military history but definitely a good read.
scvythian priestess mummy in the altai mountains
Scythian Ice Maiden - Indo-Europeans in the Altai 1/5 (https://www.youtube.com/watch?v=e4nrpkHQoxc#)
Scythian Ice Maiden - Indo-Europeans in the Altai 2/5 (https://www.youtube.com/watch?v=_AEZ0zNK5K8&feature=related#)
Scythian Ice Maiden - Indo-Europeans in the Altai 3/5 (https://www.youtube.com/watch?v=xXl9HxWXtjI&feature=related#)
Scythian Ice Maiden - Indo-Europeans in the Altai 4/5 (https://www.youtube.com/watch?v=dY65VxY30lA&feature=related#)
Scythian Ice Maiden - Indo-Europeans in the Altai 5/5 (https://www.youtube.com/watch?v=TG0ZwBRy6zk&feature=related#)
the gook locals of the altai are not related to scythians or are so race mixed that they bear no resemblance, their culture was influenced by scythians though, just like the chinese and turks were influenced by tocharians