I don't know if this helps but it looks like around 1200 to 1300 AD the 'Pattern Weld' disappears.
3000 to 2000 BC Neolithic period Around 2800, 2700 BC the first uses of meteoric iron in Egypt2500 BC the first iron tools are used in Anatolia and Mesopotamia
2000 to 1000 BC Copper and bronze period
Around 2000 BC, the Hittites living in the east of the present Turkey collect the iron ore and melt it in small furnaces. 1200 BC is the ending period of the Hittites peoples, probably the blacksmiths spread in the neighboring countries and share their knowledge. From 1500 to 1000 BC the first iron tools and weapons production centers become very active in Greece, Cyprus, Crete and Macedonia. In South India melted iron is extensively used.
1000 to 500 BC Iron period
Around 1000 BC the Greeks start to quench iron to improve the cutting characteristics of their iron weapons. From 1000 to 500 BC the Hallstatt civilization, in central Europe (present Austria area), is leading the iron period. Around 600 BC, the Persia and the Etrusquia blacksmiths know how to fire weld iron. Starting around 600 BC the India blacksmiths use the carburization technique and repeated hammering sequences to improve the iron qualities.In China, about 1000 BC, knowledge of iron-working techniques reached the country from the West. Using their kiln pottery curing knowledge the Chinese smiths produce the cast iron
500 to 400BC Iron period The use of the iron spreads all over Europe with the spread of the Celt civilization.
400 to 300BC Iron period In China the decarburization technique is used to produce steel
300 to 200BC Iron period Birth of the Wootz in South India.
200 to 100 BC Iron period In Europe, birth of the steel. The techniques used to produce steel could be based on iron selection or on carburization. The fire welding technique is used to produce iron weapons with a steel cutting edge.
100 BC to 100 AD In China hydraulic systems are used to drive the bellows
100 to 200 Birth of the Pattern Welded Steel with twist and chevron patterns in sword blades.
200 to 300 Mixing wrought iron and cast iron in their furnaces the Chineses produce steelThe Wootz is extensively used in India.
300 to 400
400 to 500
500 to 600 The "Merovigiens" use the pattern-welded steels for both their esthetical and mechanical properties.
600 to 700 The "Merovingiens" and the "Carolingiens" use the pattern-welded steels.
700 to 800 Pattern-welded steels are extensively used in Europe.
800 to 900 The "Normands" (Vikings) use pattern-welded steels for their weapons.
900 to 1000 Unceasing usage of the pattern-welded steel in Europe.Kris are made in Indonesia;Wootz steel is also produced in Turkmenistan and Uzbekistan (Ph.D. from Ann Feuerbach)
1000 to 1100 The use of the Pattern-welded steels start to decline.1095 is the first crusade year.
1100 to 1200 In Europe the welded-pattern steel is disappearing. During the crusade period, the Islamic armies are using Wootz sword blades. It's devastating