▁Netherlands ▁was ▁" in ▁onder tr ouw ▁op gen omen ". ▁Both ▁phr ases ▁mean ▁" to ▁enter ▁into ▁onder tr ouw ". ▁ ▁Pro cedure ▁▁ ▁The ▁length ▁of ▁the ▁onder tr ouw ▁period ▁can ▁vary . ▁Histor ically ▁the ▁period ▁was ▁three ▁weeks . ▁The ▁idea ▁was ▁that ▁there ▁had ▁to ▁be ▁enough ▁time ▁to ▁determine ▁that ▁all ▁legal ▁and ▁ecc les iast ical ▁requirements ▁for ▁marriage ▁had ▁been ▁comp lied ▁with . ▁ ▁In ▁the ▁Netherlands , ▁the ▁period ▁between ▁the ▁onder tr ouw ▁and ▁the ▁marriage ▁is ▁not ▁fixed . ▁However , ▁under ▁article ▁ 4 6 ▁of ▁Book ▁ 1 ▁of ▁the ▁Dutch ▁Civil ▁Code ▁the ▁maximum ▁period ▁is ▁a ▁year ▁and ▁under ▁article ▁ 6 2 ▁of ▁Book ▁ 1 ▁the ▁minimum ▁period ▁is ▁four teen ▁days ▁unless ▁an ▁exem ption ▁is ▁obtained ▁from ▁the ▁Public ▁Pro sec utor ▁( Open baar ▁Minister ie ). ▁ ▁When ▁the ▁onder tr ouw ▁is ▁registered ▁at ▁a ▁town ▁hall ▁in ▁the ▁Netherlands , ▁the ▁following ▁takes ▁place : ▁▁ ▁The ▁production ▁of ▁the ▁de ed ▁or ▁certific ates ▁of ▁birth ▁ ▁Setting ▁the ▁time ▁and ▁date ▁of ▁the ▁marriage ▁ceremony ▁( In ▁the ▁Netherlands ▁the ▁marriage ▁ceremony ▁itself ▁is ▁usually ▁held ▁at ▁the ▁town ▁hall . ▁Each ▁town ▁hall ▁has ▁a ▁special ▁hall ▁for ▁this .) ▁ ▁The ▁selection ▁of ▁the ▁witness es ▁( In ▁the ▁Netherlands ▁at ▁least ▁two ▁witness es ▁must ▁be ▁present ▁at ▁the ▁marriage ▁ceremony . ▁Their ▁presence ▁is ▁integrated ▁into ▁the ▁ceremony .) ▁