Question: When was a participant in the Battle of Maserfield abolished?

Knowledge 1: Battle of Maserfield
The Battle of Maserfield (or Maserfeld, "marsh (border) field"; Welsh: "Maes Cogwy"), was fought on 5 August 641 or 642, between the Anglo-Saxon kings Oswald of Northumbria and Penda of Mercia, ending in Oswald's defeat, death, and dismemberment. The battle was also known as "Cogwy" to the Welsh, with their countrymen from Pengwern participating in the battle (according to the probably ninth-century "Canu Heledd"), probably as allies of the Mercians. Bede reports the commonly accepted date given above; the Welsh "Annales Cambriae" is generally considered incorrect in giving the year of the battle as 644. The site of the battle is traditionally identified with Oswestry; arguments have been made for and against the accuracy of this identification. [SEP] Knowledge 2: Mercia
When Æthelflæd died in 918, Ælfwynn, her daughter by Æthelred, succeeded as 'Second Lady of the Mercians', but within six months Edward had deprived her of all authority in Mercia and taken her into Wessex.
Knowledge 1: Battle of Maserfield
The Battle of Maserfield (or Maserfeld, "marsh (border) field"; Welsh: "Maes Cogwy"), was fought on 5 August 641 or 642, between the Anglo-Saxon kings Oswald of Northumbria and Penda of Mercia, ending in Oswald's defeat, death, and dismemberment. The battle was also known as "Cogwy" to the Welsh, with their countrymen from Pengwern participating in the battle (according to the probably ninth-century "Canu Heledd"), probably as allies of the Mercians. Bede reports the commonly accepted date given above; the Welsh "Annales Cambriae" is generally considered incorrect in giving the year of the battle as 644. The site of the battle is traditionally identified with Oswestry; arguments have been made for and against the accuracy of this identification. [SEP] Knowledge 2: Nawabs of Bengal and Murshidabad
The break - up of the centralised Mughal empire by 1750, led to the creation of numerous semi-independent kingdoms (all provinces of the former Mughal empire). Nawab Siraj ud - Daulah was defeated by the British forces of Sir Robert Clive in the Battle of Plassey in 1757. Thereafter the Nawab of Bengal became a ``puppet ruler ''depending on military support from British East India company to secure their throne. Siraj - ud - Daulah was replaced by Mir Jaffer. He was personally led to the throne by Robert Clive, after triumph of the British in the battle. He briefly tried to re-assert his power by allying with the Dutch, but this plan was ended by the Battle of Chinsurah. After the defeat at Battle of Buxar and grant of the Diwani (revenue collection) of Bengal by the then Mughal Emperor Shah Alam II, to the British East India Company in August 1765 and the appointment of Warren Hastings by the East India Company as their first Governor General of Bengal in 1773, the Nawabs authority became restricted. By 1773, British East India company asserted much authority and formed the Bengal Presidency over areas ruled by the Nawabs i.e. the Bengal subah, along with some other regions and abolished the system of Dual Government. In 1793 (during Nawab Mubarak ud - Daulah's reign), the Nizamat (military power, civil and criminal justice) was abolished, British East India company thus annexed this former Mughal province as part of their empire and took complete control of the region, and the Nawabs of Bengal became mere pensioners of the British East India Company. All the Diwan offices except the Diwan Ton were also abolished.
Knowledge 1: Battle of Maserfield
The Battle of Maserfield (or Maserfeld, "marsh (border) field"; Welsh: "Maes Cogwy"), was fought on 5 August 641 or 642, between the Anglo-Saxon kings Oswald of Northumbria and Penda of Mercia, ending in Oswald's defeat, death, and dismemberment. The battle was also known as "Cogwy" to the Welsh, with their countrymen from Pengwern participating in the battle (according to the probably ninth-century "Canu Heledd"), probably as allies of the Mercians. Bede reports the commonly accepted date given above; the Welsh "Annales Cambriae" is generally considered incorrect in giving the year of the battle as 644. The site of the battle is traditionally identified with Oswestry; arguments have been made for and against the accuracy of this identification. [SEP] Knowledge 2: Hanged, drawn and quartered
Although the Act of Parliament defining high treason remains on the United Kingdom's statute books, during a long period of 19th - century legal reform the sentence of hanging, drawing, and quartering was changed to drawing, hanging until dead, and posthumous beheading and quartering, before being abolished in England in 1870. The death penalty for treason was abolished in 1998.

Answer: 918