p 207, The Berkeley Manuscripts: Joane d March 19, 1309 after 42 years of marria...

Full citation

p 207, The Berkeley Manuscripts: Joane d March 19, 1309 after 42 years of marriage (1309 - 42 = m 1267); this matches with Henry III's 51st year (1216+51=1267) and this information would also lead toa birth year for Thomas of 1243 (1267 - 24 = b 1243)

Details