Siddhartha Gautama was born a prince in the line of Sakya kings in the sixth century b.c., near present-day Lumbini.
The line of Sakya kings stretched back 500 years. 
mnli hypothesis: The line of Sakya kings stretched back 500 years.  premise: Siddhartha Gautama was born a prince in the line of Sakya kings in the sixth century b.c., near present-day Lumbini.