The English feudal barony, or "barony by tenure", now has no legal existence except as an incorporeal hereditament title or dignity. It was the highest form of feudal land tenure, namely "per baroniam" (Latin for "by barony") under which the land-holder owed the now little understood service of "being one of the king's barons". It must be distinguished from the lesser barony, also feudal, which existed within a county palatine, such as the barony of Halton within the Palatinate of Chester. Such barons were merely tenants-in-chief of a prince, whose own overlord was the king. The duties and privileges owed by feudal barons cannot now be defined exactly but the main duty certainly was the provision of soldiers to the royal feudal army on demand by the king, and a further duty, which involved considerable expense and travel, clearly also a privilege, was the attendance at the king's feudal court, the precursor of Parliament. The principal benefit clearly was the revenue generated from rents and production within the demesne lands of the barony, and also the personal power and prestige derived from the feudal service of the tenants, the highest level of whom, lords of their own manors, became knights in the baron's retinue. The estate-in-land held by barony if containing a significant castle as its "caput" and if especially large, that is to say consisting of more than about 20 knight's fees (each loosely equivalent to a manor), was termed an "honour". Constituent manors of a barony were mostly subinfeudated by the baron to his own knights or followers, with a few retained tenantless as his demesne. Most English Feudal Barons were converted to baronies of writ or peerage according to the Abolition Act of 1660. The baronies not converted became baronies of free socage, a dignity title.