Complex sentence: In 1869 an Agricultural and Forestry Institute was founded in Puławy, one of whose first students (briefly) was the future Polish writer Bolesław Prus (who had spent part of his childhood in Puławy).
Split into simpler sentences: In 1869 an Agricultural and Forestry Institute was founded in Puławy. One of its first students, briefly, was the future Polish writer Bolesław Prus (who had spent part of his childhood in Puławy).