Do you use a textbook? It should all be in the Changing Concepts part of the Acidic Environment. I'll give you the information but I've always found that if you look things up yourself, you would usually remember them better.
Lavoisier proposed that acids were substances that contained oxygen. The word "oxygen" does originate from Greek, meaning "sour taste". However, this theory is not true. Many metal carbonates which have basic properties contain oxygen. For example, Na2CO3 and MgCO3. Furthermore, hydrochloric (muric at the time) acid - HCl, does not contain oxygen.
Davy defined an acid as a substance which contained replacable hydrogen. For example, HCl can react with NaOH, producing NaCl and water. The Na has replaced the hydrogen of the HCl molecule. This is true, but gives no insight to the properties of acids.
Arrhenius said that acids were substances which ionised in solution to produce hydronium ions, and that an acid was strong if it ionised completely, and weak if it did not. However, he didn't take into consideration that ionisation is not something the acid does in isolation, but is a reaction with the solvent. Also, the strength of the acid depends not only on the acid itself, but its properties relative to that of the solvent. HCl is a strong acid in water, but in diethyl ether it is weak.
Brønsted & Lowry proposed that acids were proton donors, and bases were proton acceptors. This leads to the idea of conjugates.
Titration uses the fact that salt solutions produced from neutralisation are not always neutral. Strong acids and weak bases produce acidic salt solutions; weak acids and strong bases produce basic salt solutions; and acids and bases of equal strengths produce neutral salt solutions.
This is a very brief outline, you'll probably need more information. I recommend you read the relevant section of Conquering Chemistry.
