By the 1770s a number of guide books had been published, including Joseph Cradock's Letters from Snowdon (1770) and An Account of Some of the Most Romantic Parts of North Wales (1777). Thomas Pennant wrote Tour in Wales (1778) and Journey to Snowdon (1781/1783); though Welsh himself, Pennant had published a Tour in Scotland first, in 1769. The first of a series of British tours by another leading promoter of the picturesque, William Gilpin, was Observations on the River Wye and several parts of South Wales, etc. relative chiefly to Picturesque Beauty; made in the summer of the year 1770, but not published until 1782. Paul Sandby made his first recorded visit to Wales in 1770, later (1773) touring south Wales with Sir Joseph Banks, resulting in the 1775 publication of XII Views in South Wales and a further 12 views the following year, part of a 48-plate series of aquatints of Welsh views commissioned by Banks. This was an early example of many print series and illustrated books on Wales, often as valuable in terms of income to the artists as original works.