Three miracles were submitted to the Congregation for the Causes of Saints in Rome in October 2016 that could have led to Romero's canonization. But each of these miracles was rejected after being investigated. A fourth (concerning the pregnant woman Cecilia Maribel Flores) was investigated in a diocesan process in San Salvador that was opened on 31 January 2017 and which concluded its initial investigation on 28 February before documentation was submitted to Rome via the apostolic nunciature. The C.C.S. validated this on 7 April. On 11 August, Paglia celebrated the Romero Centenary Mass in St George's Cathedral, Southwark, in London, where the cross and relics of Romero are preserved. Subsequently, medical experts issued unanimous approval to the presented miracle on 26 October with theologians also confirming their approval on 14 December. The C.C.S. members likewise approved the case on 6 February 2018. Pope Francis approved this miracle on 6 March 2018, allowing for Romero to be canonized and the date was announced at a consistory of cardinals held on 19 May. The canonization was celebrated in Rome's Saint Peter's Square on 14 October 2018.