Yes, 5 years ago, in 2017, on the 29th of March the Guild Wars started.
For almost a year (until 18th of March '18) they were the only weekly event. Then, with coming of Boss Raids, Invasions, Towers of Doom Guild Wars became less frequent - only one week in 4. Now their total number is over 100, maybe someone can tell more exactly (I play GWs since January '18, and now it’s my 57th GWs, and about 50 before that date I missed).