Wakati wa uongozi wake kama Askofu Mkuu wa Canterbury Cranmer alianzisha mabadiliko katika mafundisho na liturgia ya Kanisa la Uingereza. Wakati wa utawala wa mfalme Henry VIII, Cranmer hakufanya mabadiliko mengi.
Chini ya mfalme Edward VI, aliyemfuata Henry VIII, Cranmer aliweza kuleta mabadiliko mengi zaidi. Alitunga matoleo mawili ya kwanza ya Kitabu cha Sala kwa Watu (Book of Common Prayer) chenye liturgia kamili kwa ajili ya Kanisa la Uingereza. Alipokea wanamatengenezo kadhaa kutoka Ulaya Bara waliofika kama wakimbizi kutoka maeneo chini ya serikali za Kikatoliki. Walimsaidia kubadilisha mafundisho kuhusu mambo kama vile ekaristi, useja wa makasisi, nafasi ya sanamu makanisani na heshima kwa watakatifu. Cranmer alieneza mafundisho mapya, pamoja na Kitabu cha sala, kwa vitabu viwili vya mahubiri (hotuba) yaliyotakiwa kusomwa na mapadre katika ibada makanisani.
Kifo chini ya Malkia Mary
Baada ya Edward VI, malkia Mary I alichukua madaraka; alikuwa Mkatoliki akalenga kurudisha nchi chini ya Kanisa Katoliki. Aliagiza kumkamata Cranmer na kumshtaki kwa uhaini na uzushi. Alipelekwa mbele ya mahakama ya mahakimu Wakatoliki pamoja na wasaidizi wawili. Wote walihukumiwa adhabu ya kifo cha kuchomwa hai motoni ambayo ilikuwa adhabu ya wazushi.
Katika miaka miwili alipokaa gerezani, Cranmer alipaswa kushuhudia kuchomwa kwa wenzake. Baadaye alijaribu kuokoa uhai wake kwa kukana mafundisho yake ya awali. Kwa kawaida angesamehewa baada ya kukana, lakini malkia Mary I hakutaka kumsamehe bali auawe. Siku ya hukumu yake aliambiwa kusoma tena ukanisho wake kanisani mbele ya watu kabla ya kufa. Cranmer alitumia nafasi hiyo kuonyesha masikitiko juu ya udhaifu wake akamtaja Papa kama mwongo na adui wa Kristo. Hivyo alichomwa akafa kama mzushi kwa Wakatoliki na mfia imani kwa Kanisa Anglikana lililoendelea baadaye kwenye misingi aliyowahi kuweka.
Avis, Paul (2005). "The Revision of the Ordinal in the Church of England 1550–2005". Ecclesiology1 (2): 95–110. ISSN1744-1366. doi:10.1177/1744136605051929.* Ayris, Paul (1993a). "God's Vicegerent and Christ's Vicar: the Relationship between the Crown and the Archbishopric of Canterbury, 1533–53". Katika Ayris, Paul; Selwyn, David. Thomas Cranmer: Churchman and Scholar. Woodbridge, Suffolk, UK: The Boydell Press. ISBN0-85115-549-9.
Ayris, Paul (1993b). "Canon Law Studies". Katika Ayris, Paul; Selwyn, David. Thomas Cranmer: Churchman and Scholar. Woodbridge, Suffolk, UK: The Boydell Press. ISBN0-85115-549-9.
Ayris, Paul (2001). "The Correspondence of Thomas Cranmer, Archbishop of Canterbury, and his English Audience 1533-54". Reformation & Renaissance Review3 (1): 9–33. ISSN1462-2459. doi:10.1558/rrr.v0i3.9.Unknown parameter |s2cid= ignored (help)* Ayris, Paul (2002). "The Public Career of Thomas Cranmer". Reformation & Renaissance Review4 (1): 75–125. ISSN1462-2459. doi:10.1558/rrr.v0i4.75.Unknown parameter |s2cid= ignored (help)* Bagchi, David V. N.; Steinmetz, David Curtis, wahariri (2004). The Cambridge Companion to Reformation Theology. Cambridge: Cambridge University Press. ISBN0-521-77662-7.
Hall, Basil (1993a). "Cranmer's Relations with Erasmianism and Lutheranism". Katika Ayris, Paul; Selwyn, David. Thomas Cranmer: Churchman and Scholar. Woodbridge, Suffolk, UK: The Boydell Press. ISBN0-85115-549-9.
Hall, Basil (1993b). "Cranmer, the Eucharist, and the Foreign Divines in the Reign of Edward VI". Katika Ayris, Paul; Selwyn, David. Thomas Cranmer: Churchman and Scholar. Woodbridge, Suffolk, UK: The Boydell Press. ISBN0-85115-549-9.
Heinze, Rudolph W. (1993). "'I pray God to grant that I may endure to the end': A New Look at the Martyrdom of Thomas Cranmer". Katika Ayris, Paul; Selwyn, David. Thomas Cranmer: Churchman and Scholar. Woodbridge, Suffolk, UK: The Boydell Press. ISBN0-85115-549-9.
Hirst, Rev E, (Vicar of St. Paul’s Stockport) (1934). "Archbishop Cranmer". Churchman Journal48 (2): 2. Ilihifadhi kwenye nyaraka kutoka chanzo mnamo 7 November 2018. Iliwekwa mnamo 7 November 2018.Unknown parameter |url-status= ignored (help); Check date values in: |archivedate=, |accessdate= (help)
Loades, David (1993). "Thomas Cranmer and John Dudley: An Uneasy Alliance, 1549–1553". Katika Ayris, Paul; Selwyn, David. Thomas Cranmer: Churchman and Scholar. Woodbridge, Suffolk, UK: The Boydell Press. ISBN0-85115-549-9.
Matthew, H. C. G.; Harrison, Brian Howard, eds. (2004). "Oxford Dictionary of National Biography". Oxford Dictionary of National Biography. Oxford: Oxford University Press. OCLC56568095
Selwyn, D. G. (1993). "Cranmer's Library". Katika Ayris, Paul; Selwyn, David. Thomas Cranmer: Churchman and Scholar. Woodbridge, Suffolk, UK: The Boydell Press. ISBN0-85115-549-9.
Spinks, Bryan D. (1993). "Treasures Old and New: A Look at Some of Thomas Cranmer's Methods of Liturgical Compilation". Katika Ayris, Paul; Selwyn, David. Thomas Cranmer: Churchman and Scholar. Woodbridge, Suffolk, UK: The Boydell Press. ISBN0-85115-549-9.
Stevenson, Kenneth W. (1993). "Cranmer's Marriage Vow: Its Place in the Tradition". Katika Ayris, Paul; Selwyn, David. Thomas Cranmer: Churchman and Scholar. Woodbridge, Suffolk, UK: The Boydell Press. ISBN0-85115-549-9.
Strype, John (1840) . "Chapter 28". Historical and Biographical Works: Memorials of Thomas Cranmer.