House of Lancaster to members of the family and their supporters. The family provided England with three kings: Henry IV, who ruled from 1399 to 1413, Henry V (1413–1422), and Henry VI (1422–1461 and 1470–1471). The House became extinct in the male line upon the murder in the Tower of London of Henry VI, following the battlefield execution of his son Edward of Westminster, Prince of Wales, by supporters of the House of York in 1471. Lancastrian cognatic descentfrom John of Gaunt and Blanche of Lancaster's daughter Phillipacontinued in the royal houses of Spain and Portugal while the Lancastrian political cause was maintained
IEEE 1471 of software-intensive systems". It has long been recognized that "architecture" has a strong influence over the life cycle of a system. However, until relatively recently, hardware issues have tended to dominate architectural thinking, and software aspects, when considered at all, were often the first to be compromised under the pressures of development. IEEE 1471 was created to provide a basis for thinking about the architecture of software-intensive systems. IEEE 1471's contributions can be summarised as follows (in this list, items in "italics" are terms defined by and used in the standard): IEEE 1471 provides informative annexes that relate its concepts