For Panther [10.3.x] and earlier MacOS X'es, one can use 'TinkerTool' v. 3.3c.
For Tiger [10.4.x] and earlier MacOS X'es, consider 'TinkerTool' v. 3.4.
Each allow the number of 'History' links displayed in the 'History' menu to be 0 through 30, in increments of 5.
Each allow the overall number of 'History' links maintained to be 0, 500, 1000, 2000, or 3000.
'TinkerTool' is available at 'http://www.bresink.de/osx/'.
An alternative - via 'Terminal' ['/Applications/Utilities/'] enter:
'defaults write com.apple.Safari RecentHistoryMenuItemsLimit 22' and press <return>.
Naturally, you may substitute the '22' with any number from 0 to x.
I entered 50 '9's (9...9) for x, and the value was accepted. I then reset x to a sensible value of 50.
'defaults write com.apple.Safari WebKitHistoryItemLimit 800' and press <return>.
Naturally, you may substitute the '800' with any number from 0 to x.
I entered 50 '9's (9...9) for x, and the value was accepted. I then reset x to a sensible value of 1000.
Using large values for either, and / or both, may have some affect on 'Safari's overall performance.
The above 'defaults ... ' lines apply to both 'Safari's of Panther and Tiger.