the Battle of Vegkop. 1837 - Piet Retief publishes his Manifesto. - Andries Potgieter and Piet Uys , helped by Rolong and Griqua tribes, defeat Ndebele at Mosega. - Louis Trichardt arrives in Lourenco Marques . - Seperate administrative districts granted to Port Elizabeth , Cradock and Colesburg. 28 March 1837