The oldest attestation of jatts is in Sindh where they were mentioned as one of the main tribe of Sindh whom Arabs encountered after Muhammad Bin Qasam's conquest of Sindh in 711 AD. They were described by muslim arab historians of the time as an oppressed community of pastrolist animal herders at the hand of tyrant brahmin ruler of sindh Raja Dahir , the reason was that Jatts in sindh were following bhuddism at that time which Brahmins with help of remanant fanatic kshatriyas were eliminating to revive hinduism in the north west of south asia in places like Sindh, Gandhara and Kashmir.
Jatts gradually moved northwords into plains of punjab. They remained predominantly pastrolist animal herders (like nomadic Gujjars of kashmir) with little bit of agriculture until the time of the mughals when agriculture saw a boom starting in 1500s due to the introduction of persian irrigation wheel that made agriculture more professional than ever before after which jatts of punjab gave up pastolist way of life and founded many agricultural villages throughout punjab and achieved such excellence in agriculture that jatt became an equivalent word as farmer in punjab society.
Pastrolist Jatt remanants still live in their native Sindh and neighboring balochistan where they are engaged in pastrolist animal herding and animal (camel) trade. Actually many of so-called Baloch tribes are of ancient jatt origin who have adopted balochi language and identity due to the dominance of neighboring Baloch tribes. Many so-called baloch tribes of sindh and balochistan such as "Jatoi", "chandio" and so on are ultimately of indigenous sindhi pastrolist jatt origin.
Similarly many clans in punjab who now identify as jatts were not historically descended from pastrolist jatts of sindh but were degraded hindu kshatriya clans of punjab who took to agriculture centuries ago and assimilated in modern jatt punjabi identity.
