He landed just above the town of Petrockstow or Padstow, then called Laffenac or Lodenic.  Here he found some harvesters from whom he begged some water, the supply of which had probably run out during the voyage.  They treated him with incivility and bade him find a spring for himself; this he did by driving his staff into the ground.  The inhabitants of this part of Cornwall were at the time only partly converted to Christianity, but St Samson was already at Padstow, his cell being in what is now the garden of Prideaux Place; on Petroc’s arrival Samson yielded the field to his brother in the Faith and departed on his travels.  Petroc remained in the neighbourhood of Padstow for about thirty years, preaching the gospel and gathering round him a band of monks.  Like all the British saints, he practised the most rigid asceticism, and there is no doubt that the austerity of those early missionaries made the deepest impression on the emotional Celtic tribes.

One of the most remarkable practices was that of praying in the water of wells and rivers and St Petroc is said to have spent much of his time sitting up to his neck in the Little Petherick river reciting the psalter.  His food was bread and water, with porridge on Sundays.