 for instance to strengthen the patent in view of some newly discovered prior art documents and/or in advance of envisaged litigation) was to request such limitation at the national level, i.e.before the national patent offices or competent courts of the Contracting States, if permitted.The EPC of 1973 made no provision for a limitation procedure, and "a fortiori" no provision for centrally limiting a European patent before the EPO after the nine-month period for filing an opposition (nine months as from the date of grant of the European patent).