On July 29, 1966 — a Friday — the Fillmore Auditorium opened a two-night run headlined by Them, the Belfast band fronted by Van Morrison, with San Francisco's own Sons of Champlin in support. The poster is BG-20, drawn by Wes Wilson (wolfgangs.com BG020; trps.org; dking-gallery.com BG#20-2; the Met holds a copy in its collection).

What makes the date stick isn't the bill so much as a story that gets told about what happened between the two shows — a story I'd handle with tongs. The well-circulated version goes like this: after opening night, Van Morrison went out drinking with Bill Champlin of the Sons of Champlin, Morrison was in rough shape for the second night (July 30), and Bill Graham, blaming Champlin, banned the Sons from his venues for something like two years afterward. The trouble is that the better source doesn't support it. The rockprosopography101 performance list for the Sons of Champlin tells the drinking anecdote itself as "according to legend" and makes no mention of any ban; the "two-year ban" traces instead to a looser band history. Worse for the anecdote, one eyewitness retelling pins Graham's anger not on Van's condition at all but on Champlin throwing microphones into the crowd during a James Brown number — and names the song as "Cold Sweat," which James Brown didn't release until 1967, a year after this show. When a story's own supporting detail is anachronistic, that's a signal. So take the bar night and the ban as scene folklore, not documented fact; what's solid is the poster, the bill, and the two nights.

There's a poignancy to the timing regardless of the drinking story. This run sat near the end of Them's 1966 US tour; the band was close to finished, and Van Morrison would shortly go solo — "Brown Eyed Girl" arrived in 1967. So the Fillmore caught Them on the way out, a headliner already dissolving, sharing a stage with a local band that was, by most accounts, just getting started. If Graham did hold a grudge, the irony is that the Sons of Champlin outlasted the very tour that occasioned it.

Across town the same Friday, the Avalon Ballroom was running its own show: Bo Diddley with Quicksilver Messenger Service, the second night of the FD-18 run. The poster is the Stanley Mouse and Alton Kelley piece that parodies the old RCA "Voice of Music" trademark. FD-18's opening night was the night before, July 28 — so on this date it's night two. That gives July 29, 1966 a neat symmetry the scene rarely staged so cleanly: a Wes Wilson Fillmore poster and a Mouse/Kelley Avalon poster hanging over the same city on the same Friday night, the two houses and their two house artists running head to head.

A year later the date landed on a Saturday, and July 29, 1967 was, if anything, the richer night. The Fillmore had the Doors, with the James Cotton Blues Band and Richie Havens — the Doors' half of a split run, poster BG-75 by Bonnie MacLean, and they were riding "Light My Fire" through that summer. The Avalon countered with Blue Cheer, Captain Beefheart, and the Youngbloods on FD-73 (art by Tom Glass), night three of its own run. Two ballrooms, two strong bills, two more posters — 1967 is the year this particular calendar square earns its keep.

Before the scene, there's nothing to report: July 29, 1965 predates the ballroom era, so that year is simply blank.

For 1968 and 1969, honesty is the only responsible move. I couldn't confirm a specific San Francisco ballroom bill for July 29 in either year from vetted sources this pass, so I'm not going to manufacture one. The context that makes the silence plausible: by 1968–69 Graham had moved his operation to Fillmore West, and the Avalon was winding down toward its close — the map that produced those tidy 1966 and 1967 face-offs had already changed. But "plausible silence" is still silence, and I'd rather leave 1968 and 1969 marked as gaps than fill them with something I can't cite.

So what July 29 really offers is one strong story and one clean coincidence. The story is Them's short, unraveling Fillmore stand and the bar night that — if the anecdote holds — cost the Sons of Champlin two years of Graham's rooms. The coincidence is the Wilson-versus-Mouse/Kelley split across town that same night. Take the ban detail with the grain of salt the sources ask for, enjoy 1967 as the loaded runner-up, and let 1968 and 1969 stand honestly empty.