Complex sentence: Henry IV gave them the twice-yearly right of frankpledge and the right of waif and stray and the return of briefs and writs which gave the priory a steady income from rents, fines, licences and other fees.
Split into simpler sentences: Henry IV gave them the twice-yearly right of frankpledge and the additional right of waif and stray and the return of briefs and writs. These grants gave the priory a steady income from rents, fines, licences and other fees.