Historical clue formulations

• Iconic August 1969 music festival, four of whose performers appear in the answers to 17-, 36-, 46- and 55-Across — 2019-08-14
• Ravi Shankar was part of it — 2003-08-29
• 1969 event attended by hippies — 1999-05-24
• Strip's smallest character — 1997-11-23