my $aa = "Accepted and agreed to by Jerry Smith as of the 1st day of November 2005.";

if ( 	$aa =~ m{
	(?:as of)*
	(?:\s|\n)*	#for any possible space or line end	
	(?:this|the)*
	(?:\s|\n)*	#for any possible space or line end			
	(
	(?:[1-31])      #day, 1 to 31
	(?:st|nd|rd|th) #for all the cases like 1st, 2nd, 3rd, 25th
	(?:\s|\n)*      #for any possible space or line end
	(?:day of)*
	(?:\s|\n)*      #for any possible space or line end
	(?:January|February|March|April|May|June|July|
	August|September|October|November|December)
	(?:\s|\n)*	#for any possible space or line end
	(?:\,|\s)*      #for any possible space or comma end
	(?:\s|\n)*      #for any possible space or line end
	([1,2]\d{2,3})  #year
	)
	(?:\,|\.|\s)*
	(?:[ ]{2}|\n|\z)*   #Two spaces, newline, or string end
	}ixmsg)	{
				
		print $1;
	}