A new alliance with England was sealed in the 1386 Treaty of Windsor; a year later Joao of Avis married Philippa of Lancaster, the daughter of John of Gaunt.
A new alliance was formed with England in the 1386 Treaty of Windsor just one year before Joao of Avis married Philippa of Lancaster.
For case studies in particular, there must be an empirical basis for instance selection and assurance of adequate population homogeneity.