Septimus Hodge, one of the main characters from the early 19th century parts of the play "Arcadia" by Tom Stoppard. He is the tutor of the young genius Thomasina Coverly.
Septimus is the name of the hero in the Septimus Heap series, the first of which is Magyk. As the seventh son of a seventh son, he has strong magical (or I should say magykal) powers. He is, in the first book, unsure of himself, being raised as 'boy 412' of the young army. The book is very fun and often funny, and very interesting throughout. Septimus himself is a polite and generous character.
Lord Septimus is a character in Neil Gaiman's novel Stardust. The 7th and youngest of the Lords of Stormhold, he succeeded in murdering the majority of his family in order to succeed to the throne.
This is the name of the hero in Showell Styles' Midshipman Quinn books. He is a very intelligent, courteous, quick-thinking midshipman in the British navy, and consequently, that is the picture I have with this name. Very positive.