13th-century introductions

thumb|Gargoyles of Notre-Dame de Paris thumb|Dragon-headed gargoyle of the Tallinn Town Hall, [[Estonia]] thumb|Gargoyle of the Vasa Chapel at Wawel in [[Kraków, Poland]]

divisions of the Bible

symbol used in heraldry to denote the Irish province of Ulster

positional numeral system system developed by the Cistercian monastic order in the early 13th century with a single glyph indicating any integer from 1 to 9999

thumb|Poleyn, 1555–60 The poleyn or genouillere was a component of Medieval and Renaissance armor that protected the knee. During the transition from mail armor to plate armor, this was among the earliest plate components to develop. They first appeared around 1230 and remained in use until 1650, when firearms made them obsolete.