Outstanding sword, DhaDha!  Thanks for sharing it. 
 
Based on the repousse work and blade markings, however, I would place the age of your sword a bit later than the Ayutthaya period and would lean more towards the late 18th/early 19th century (Rattanakosin period).   Many pieces from this period evoke or are in a "revival" of Ayutthaya design. 
 
Here is an example from my collection with similar silver work dating to the early 19th C.:
		 
		
		
		
			
		
		
		
		
		
		
		
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