I can only give some descriptions on the changes throughout history. The essence basically remains the same throughout history: the mass of the catechumens and the eucharistic liturgy proper. Initially Mass was offered only on Sundays and feast days, but as more feast days were inserted, daily masses began to be offered.

Changes were made throughout history: additional prayers, or changes in the order of prayers. But the Canon of Mass, the core eucharistic prayer in the eucharistic liturgy, has more or less been the same in Rome since Pope Gregory I (600 AD) to 1500 AD. Elsewhere there is more variation, and only unified by Pope Pius V in 1570 after the Council of Trent.

The liturgy in 500 AD compared to 1000 and 1500 AD was simpler, with fewer prayers, graduals, and no Credo, just to mention a few. It should therefore be shorter, but since the medieval ages sometimes did not have sermons, the length could be the same. A Tridentine mass (after 1500s) could reach 3 hour long in high mass form with a sermon.

If you're curious, the liturgy of John Chrysostom (4th century) is still performed in Eastern Orthodox churches today every Sunday morning with very little difference, except a few: Pews wouldn't have been there; catechumens would be standing in the back, in the narthex, and would leave after the catechumen prayers mid-way through; non-Christians would also leave mid-way through, before the eucharist; men and women would be on separate sides of the aisle. Besides these minor differences though, attend pretty much any Eastern Orthodox Sunday morning liturgy and it's word-for-word (translated) the same one done in the fourth century as written by John Chrysostom.