John Oldcastle was born in 1370 and in 1397 inherited his family estates, which included a manor in
Almeley as well as lands in
Kinnersley and Letton, Herefordshire, and property in and around
Hereford. In July 1397, Oldcastle accompanied two Mortimer family
retainers to Ireland, later serving under
Roger Mortimer. Oldcastle was knighted in 1400, and took part in a campaign against Scotland the same year. In the aftermath of the 1401 outbreak of the
Glyndŵr Rising, Oldcastle was appointed captain of Built and later Hay. In January 1404, Oldcastle briefly gained a Parliament seat representing
Herefordshire, and was subsequently ordained a country bench member and, finally, sheriff. His loyal service during the pacification of Wales brought him 40 pounds of annuities and an additional issue of 40 marks in 1406. In 1408, he further increased his material wealth by marrying baroness
Joan Cobham, thus inheriting lands in
Norfolk,
Northamptonshire,
Wiltshire and
Kent. Oldcastle's religious beliefs were considerably influenced by
Lollard cleric William Swynderby, who preached in Almeley during his youth. Lollardy was a politico-religious movement initiated by prominent theologian
John Wycliffe in the 1370s during his service in the
University of Oxford. Lollard beliefs were outlined in the 1395
The Twelve Conclusions of the Lollards, which dealt with their opposition to
capital punishment, rejection of
clerical celibacy, and belief that members of the clergy should be tried by the civil courts. The Conclusions also rejected
Christian pilgrimages and
Christian art inside the churches, which were alleged to take away from focus on God during religious worship. Also denounced in the Conclusions were war, violence, and abortion. Increasingly radicalised in the years that followed, Oldcastle wrote letters to
Hussite leaders
Wok of Waldstein and
Wladislas of Zwierzeticz, congratulating them on their opposition to the mainstream clergy. The
anti-clerical legislation promoted during the inaugural 1410 Parliament session is also considered to be penned by Oldcastle. In 1411, Oldcastle participated in the expeditionary force sent by England in support of Burgundy in its
war with Armagnac. Fighting under the command of
Henry, Prince of Wales, the pair strengthened their friendship, which was established during the Welsh campaign. The rise of Lollardy alarmed archbishop
Thomas Arundel, who unsuccessfully accused Oldcastle of promoting heretical teachings within his estates on several occasions, despite Henry's reluctance to allow the Church to prosecute a close personal friend. By August 1413, King Henry grew tired of Oldcastle's insubordination, permitting Arundel to prosecute him. Arundel summoned Oldcastle to appear in the
Leeds Castle on 11 September 1413, but Oldcastle ignored the call and retreated to
Cooling Castle, his keep. Arundel immediately excommunicated the defendant, ordering him to receive judgement on 23 September. On the same day, Oldcastle was brought to the
Tower of London, accusing the
Pope of being the
Antichrist, dismissing the adoration of the cross and the
Sacrament of Confession. Following his statements, Oldcastle was charged as a heretic and condemned to execution; Henry intervened once more, giving the inmate forty days to repent. Oldcastle seized the opportunity, escaping on 19 October with aid of a group of London Lollards led by William Parchmyner, and later going into hiding at latter's house in
Smithfield. ==Revolt==