Complex sentence: Newton tried unsuccessfully to obtain one of the two fellowships that exempted the holder from the ordination requirement, but at the last moment in 1675 he received a dispensation from the government that excused him and all future holders of the Lucasian chair.
Split into simpler sentences: Newton tried unsuccessfully to obtain one of the two fellowships that exempted the holder from the ordination requirement. At the last moment in 1675 he received a dispensation from the government that excused him and all future holders of the Lucasian chair.