Complex sentence: St. Joseph's School is the oldest missionary school in the Kashmir valley, it is the pioneer of education not only for Baramulla but for the whole of north Kashmir which has produced the brightest and the best of the valley across a century.
Split into simpler sentences: St. Joseph's School is the oldest missionary school in the Kashmir valley. It is the pioneer of education not only for Baramulla but for the whole of north Kashmir which has produced the brightest and the best of the valley across a century.