Physically many cats are able to get pregnant as young as only six or seven months old. However, it is better and healthier for pregnancy to occur when they're a little older. Often younger cats are not good mothers; the maternal instinct seems to be better developed when they're one year or older.
Initially, all modern linguistics was historical in orientation. Even the study of modern dialects involved looking at their origins. Ferdinand de Saussure 's distinction between synchronic and diachronic linguistics is fundamental to the present day organization of the discipline.
Historical archaeology is the study of cultures that existed (and may still) during the period of recorded history--several thousands of years in parts of the Old World, but only several hundred years in the Americas.