LONDON.- One of the largest and most important sets of portraits of early English kings and queens is to go on display at the National Portrait Gallery for the first time in 36 years. The 16 portraits, from William I to Mary I, are usually on loan to Montacute House, Somerset, but have been brought to the National Portrait Gallery as part of the Making Art in Tudor Britain research project. The portraits and the results of the research feature in a display Picturing History: A Portrait Set of Early Kings and Queens from 19th July – 4th December before being returned to Montacute House. Between March and May these paintings underwent technical analysis including dendrochronology (tree-ring dating), infra-red analysis, x-radiography, paint sampling and microscopy. Prior to the research it was thought that the set comprised of at least two groups of portraits: the first painted in the 1590s, and the second thought to have been painted in the 1620s.