Walter Bigg was born in Wallingford in 1605. He was apprenticed to a relative in London and became a Merchant Taylor. Bigg prospered in London and acquired land around St Giles in the Fields. During the Civil War, he fought with Parliament and took part in the siege of Basing House.
By 1646 he had become a liveryman of the Merchant Taylors’ Company and by 1653 he was on the Court, had become an alderman and was serving as a Sheriff. The following summer, he was elected Master of the Merchant Taylors’ Company.
In 1658 Bigg moved back to Wallingford, leaving his property in St Giles to finance a school in his home town. With these funds, six poor boys were able to be educated free of charge. In the early years, the Merchant Taylors’ Company provided £10 a year towards the schoolmaster’s salary.