Complex sentence: During the Ottoman period the town was known as "Kesri", and it was not until the 1960s that the village underwent a considerable increase in density and population and started to be generally referred to by its current name, Özdere.
Split into simpler sentences: During the Ottoman period the town was known as "Kesri". In the 1960s that the village underwent a considerable increase in density and population and started to be generally referred to by its current name, Özdere.