changelog: add prehistory

CHANGELOG.md

@@ -35,10 +35,9 @@ type BlockMeta struct {
 }
 ```
 
+- `ValidatorSet.Proposer` is exposed as a field and persisted with the `State`. Use `GetProposer()` to initialize or update after validator-set changes. 
+
 - `tendermint gen_validator` command output is now pure JSON
-- `ValidatorSet` data type:
-	- expose a `Proposer` field. Note this means the `Proposer` is persisted with the `State`.
-	- change `.Proposer()` to `.GetProposer()`
 
 FEATURES:
 
@@ -218,3 +217,19 @@ BUG FIXES:
 
 - Various fixes to WAL and replay logic
 - Various race conditions
+
+## PreHistory
+
+Strict versioning only began with the release of v0.7.0, in late summer 2016.
+The project itself began in early summer 2014 and was workable decentralized cryptocurrency software by the end of that year.
+Through the course of 2015, in collaboration with Eris Industries (now Monax Indsutries), 
+many additional features were integrated, including an implementation from scratch of the Ethereum Virtual Machine.
+That implementation now forms the heart of [ErisDB](https://github.com/eris-ltd/eris-db).
+In the later half of 2015, the consensus algorithm was upgraded with a more asynchronous design and a more deterministic and robust implementation.
+
+By late 2015, frustration with the difficulty of forking a large monolithic stack to create alternative cryptocurrency designs led to the 
+invention of the Application Blockchain Interface (ABCI), then called the Tendermint Socket Protocol (TMSP).
+The Ethereum Virtual Machine and various other transaction features were removed, and Tendermint was whittled down to a core consensus engine
+driving an application running in another process. 
+The ABCI interface and implementation were iterated on and improved over the course of 2016,
+until versioned history kicked in with v0.7.0.