A descendant of Proto-Algic, Proto-Algonquian, diverged and spread east, likely around 1000 BC, the ancestor of the Algonquian languages which form the bulk of known Algic languages, spoken in the northern and eastern parts of the United States and Canada east of the Rockies all the way to the coast. The exact location where Proto-Algonquian was spoken is likely in the Northwest Plateau region, possibly Idaho where the westernmost Algonquian languages are spoken, but multiple regions between there and just west of the Great Lakes have been posited. Algonquian languages splintered off as they moved eastward, probably facilitated by the spread of the mound-builder cultures that developed in the Adena (1000–200 BC) and Hopewell (200–500 AD) cultural periods.