Note: I have chosen to include the 'spell' Apollonius used to create a horcrux so that you can see what he said and what it all meant. This spell is included "Out of Character", so although you can read it here, your characters do not know the spell and cannot use it without instruction in its use.
The spell-caster has killed a person as a sacrifice for the creation of a horcrux and begins the horcrux-creation spell with a memorial of this, saying:
Ego quî interfêcî necâvîque mê sîcarius homicîdaque fêcî; in alacritâtem furôremque mortis animus mêus pannôsus bacchâtur!
(I who have destroyed and killed have made myself a murderer and a homicide; In the ecstasy and frenzy of death my tattered soul revels)
The spell-caster turns his wand on himself, saying:
Ita vêrô, cum caedis aviditâte in sacrâmentum diabolî juxtâmortâle hoc virgam mêam in animô pannôsô meô vertô: eum cruciô!
(Truly, therefore, with murder-lust in this deathly devil's sacrament I turn my wand upon my own tattered soul: I crucify it!)
The spell-caster has used the cruciatus curse on himself then drinks the chalice of the sacrifice's blood, saying:
Hûc nunc ad viscerâtiônem hanc hostiae cruciâtae sanguine pôtô huius ignem occultum imbibô aninmum pannôsum cruciâtumque mêum cruentiâre!
(Here, now, at this visceration I drink the crucified sacrifice's blood and imbibe its secret fire to bloody my tattered and crucified soul!)
The spell-caster, at last, turns his wand on the vessel which will house the torn part of his soul and become his horcrux, saying:
Ego quî peccâtum maximum contrâ nâtûram commîsî quî cum sanguine frigidô entem vîvum interfêcî necâvîque nunc in hâc hôrâ tenebrôsâ peccâtum maximum contrâ animum committô: animum pannôsum cruciâtum cruentumque mêum scindô lacerô perdîlaniôque et prôvocantî animulâ mêâ eam, fragmentum înfêlîx flêbileque cêlô abdôque et, pônentî receptâcûlô hôc vâse hôc nunc concêdô!
(I who have committed the greatest sin against nature, who have destroyed and killed in cold blood, now, in this dark hour commit the greatest crime against the spirit: I tear, lacerate and thoroughly rip apart my own tattered, crucified and bloody soul and, summoning the soul-piece, I secrete it and hide it away, a wretched and pitiful fragment, by placing it in this receptacle—in this vessel— and in this way I now vouchsafe it!)
by 
Subject: The Horcrux Spell 
