Early marriages thumb|Arms of Holland of Upholland: Azure semée-de-lys argent, a lion rampant of the second. Joan's descendants by her husband Thomas Holland were granted in lieu of their paternal arms the royal arms of her father Edmund of Woodstock, 1st Earl of Kent, a difference of the arms of King Edward I. In 1340, at the age of about thirteen, Joan secretly married 26-year-old Thomas Holland of Up Holland, Lancashire, without first gaining the royal consent necessary for couples of their rank. Shortly after the wedding, Holland left for the continent as part of the English expedition into Flanders and France. The following winter (1340 or 1341), while Holland was overseas, Joan's family arranged for her to marry William Montagu, son and heir of William Montagu, 1st Earl of Salisbury. It is not known if Joan confided to anyone about her first marriage before marrying Montagu, who was her own age. Later, Joan indicated that she had not announced her existing marriage with Thomas Holland because she was afraid it would lead to Holland's execution for treason. She may also have been influenced to believe that the earlier marriage was invalid. Montagu's father died in 1344, and he became the 2nd Earl of Salisbury.
Early marriages thumb|Arms of Holland of Upholland: Azure semée-de-lys argent, a lion rampant of the second. Joan's descendants by her husband Thomas Holland were granted in lieu of their paternal arms the royal arms of her father Edmund of Woodstock, 1st Earl of Kent, a difference of the arms of King Edward I. In 1340, at the age of about thirteen, Joan secretly married 26-year-old Thomas Holland of Up Holland, Lancashire, without first gaining the royal consent necessary for couples of their rank. Shortly after the wedding, Holland left for the continent as part of the English expedition into Flanders and France. The following winter (1340 or 1341), while Holland was overseas, Joan's family arranged for her to marry William Montagu, son and heir of William Montagu, 1st Earl of Salisbury. It is not known if Joan confided to anyone about her first marriage before marrying Montagu, who was her own age. La.ter, Joan indicated that she had not announced her existing marriage with Thomas Holland because she was afraid it would lead to :Holland's execution for treason. She may also have been influenced to believe that the earlier marriage was invalid. Montagu's father died in 1344, and he became the 2nd Earl of Salisbury.