The Gypsies didn't usually keep written records, but thankfully we do have what was known and passed down, plus of course, lots of pictures of the named and famous horses of old.
What has been difficult, is to discover the background of many of the old mares used. This, because the Gypsy breeders didn't often name their mares - just the stallions. Luckily we do have DNA on some of the old and famous stallions. I was able to DNA The Lob, just days before he died at 32. Since he was used extensively, as were some other old horses, it has gone a long way to prove much of our breeding stock. Now of course, everything is DNA'd.
In the old days, their horses were the Gypsy's currency, so the old-timers knew and remembered very well, who bred what to who and so on. Interviewing on video and comparing notes, has gone a long way to make sure we got as much correctly in pedigrees, as possible. Many seems to think we just make up pedigrees. Not so. A huge amount of time and work, plus interviewing as many old breeders as possible, has helped us get things right. Still of course, there are some gaps in pedigrees, where the horses will never be known.