His name is variously given as Napper or Napier. From the Catholic Encyclopedia:
English martyr, born at Holywell manor, Oxford, 1550; executed at Oxford 9 November, 1610. He was a son of Edward Napper (d. in 1558), sometime Fellow of All Souls College, by Anne, his second wife, daughter of John Peto, of Chesterton, Warwickshire, and niece of William, Cardinal Peto. He entered Corpus Christi College 5 January, 1565-6, but was ejected in 1568 as a recusant. On 24 August, 1579, he paid a visit to the English College at Reims, and by December, 1580, he had been imprisoned. He was still in the Wood Street Counter, London, on 30 September, 1588; but was liberated in June, 1589, on acknowledging the royal supremacy.
He entered the English College, Douai, in 1596, and was sent on the mission in 1603.
He appears to have lived with his brother William at Holywell. He was arrested at Kirtlington, four miles from Woodstock, very early in the morning of 19 July, 1610, when he on him a pyx containing two consecrated Hosts as well as a small reliquary. Brought before Sir Francis Eure at Upper Heyford (Wood says before a justice named Chamberlain), he was strictly searched; but the constable found nothing but his breviary, his holy oils, and a needle case with thread and thimble. The next day he was sent to Oxford Castle, and indicted at the session soon after under 27 Eliz., c. 2 for being a priest. The possession of the oils was held to be conclusive and he was condemned, but reprieved. In gaol he reconciled a condemned felon named Falkner, and this was held to aggravate his crime, but as late as 2 November it was believed that he would have his sentence commuted to one of banishment.
As he refused the oath of allegiance, which described the papal deposing power as a "false, damnable, and heretical" doctrine, it was decided to execute him.
He suffered between one and two in the afternoon, having said Mass that morning. His head according to Wood was set up on Tom Gateway; according to Challoner's less probable statement on Christ Church steeple. His quarters were placed on the four city gates, but at least some were secretly removed, and buried in the chapel (now a barn) of Sanford manor, formerly a preceptory of Knights Templar.
In October of 2010 (just a month after Pope Benedict XVI's visit to Scotland and England), Archbishop Bernard Longley of Birmingham dedicated a plaque to the martyr:
During his homily Archbishop Longley said: "Today we gather as pilgrims to celebrate the Mass of the Martyrs of Oxford University and to commemorate the 400th Anniversary of the martyrdom of Blessed George Napier. As pilgrims we are part of a long tradition of Christians setting out from home on a journey of faith to some place particularly associated with the life of our Lord - of those most closely associated with him as Christian witnesses.
"The life of a pilgrim is touched and transformed through the experience of pilgrimage and of the ways that are linked with the life and witness of the saints we honour. For us this pilgrimage is characterised by the fidelity to the Church and teaching of Christ demonstrated by Blessed George Napier and his companion martyrs – and by the courage of the Holy Spirit at work within them and strengthening them in the final act of love and of witness in this city."
The Archbishop of Birmingham said: "The lives of our martyrs were taken from them because they adhered to their faith in Christ within the Catholic Church. Their witness is echoed for me whenever we sing the beautiful words of Blessed John Henry Newman: 'And I hold in veneration, For the love of him alone, Holy Church as his creation, And her teaching as his own.'"
Archbishop Bernard Longley concluded:
"One month ago an apostolic witness came to strengthen our faith. We continue to benefit from the impact of Pope Benedict’s visit to this diocese. Paradoxically in the time of Blessed George Napier and his companions the role of faith as the foundation of civil society was hardly questioned, yet the liberty to practice faith was narrowly defined.
"Today the Holy Father has reminded us of the importance of faith in strengthening civil society and of the opposition we can encounter. He said: 'There are some who now seek to exclude religious belief from public discourse, to privatise it or even to paint it as a threat to equality and liberty. Your religion is in fact a guarantee of authentic liberty and respect, leading us to look upon every person as a brother or sister."
You may see a picture of the plaque here.