The High Middle Ages, or High Medieval Period, was the period of European history that lasted from around AD 1000 to the 1300s. The High Middle Ages were preceded by the Early Middle Ages and were followed by the Late Middle Ages, which ended around AD 1500 (by historiographical convention).
The Late Middle Ages or Late Medieval Period was the period of European history lasting from AD 1250 to 1500. The Late Middle Ages followed the High Middle Ages and preceded the onset of the early modern period (and in much of Europe, the Renaissance). Around 1300, centuries of prosperity and growth in Europe came to a halt.