Chronological Order of Hogwarts' Headmasters

[SlytherinTears]

There isn't much information on when previous Headmasters/Headmistresses of Hogwarts served, so I was wondering if anyone had a vague idea of the order of known headmasters.

I know Dumbledore succeeded Dippet, but that is the only two headmasters that I am sure of.

[luinrina]

There's Phineas Nigellus Black (Sirius' great-great-grandfather) who was born 1847. He attended Hogwarts from either 1858 to 1864 or 1859 to 1865. His youngest child was born in 1889. I think he might have been headmaster once his children were grown up and had families of their own. (see the Black Family tree on the HP online lexicon)

Dilys Derwent: Headmistress of Hogwarts 1741 - 1768

An Everard: No family name is given, as aren't any dates known of him. But he seemed to be famous for his portrait hang in many wizarding institutions, like the Ministry.

No dates were given for Dexter Fortescue, either.

Other information doesn't exist. At least, the lexicon isn't offering more on that. I think it's up to you to fill the vast black holes.

EDIT: Dolores Umbridge was for a while headmistress in 1996 (Harry's fifth year, OotP), and Severus Snape was headmaster in 1997/1998.