diff --git a/NOTEPAD.md b/NOTEPAD.md
index 0d45245..f0e91f2 100644
--- a/NOTEPAD.md
+++ b/NOTEPAD.md
@@ -1,15 +1,8 @@
 # History
 
-```shell
-teams: [[player]]
-weights: [[f64]]
-results: [f64]
+```rust
+let mut history = History::new();
 
-player: (gaussian, f64, f64)
-
-players: [player]
-weights: [f64]
-
-
-teams: [([(player, weight)], result)]
+let agent_a = history.new_agent();
+let agent_b = history.new_agent_with_prior(Prior::new(Gaussian::default(), BETA, GAMMA));
 ```
diff --git a/src/history.rs b/src/history.rs
index 37829df..4a09dc4 100644
--- a/src/history.rs
+++ b/src/history.rs
@@ -247,7 +247,7 @@ impl History {
         results: Vec<Vec<f64>>,
         times: Vec<i64>,
         weights: Vec<Vec<Vec<f64>>>,
-        priors: HashMap<Index, Player>,
+        mut priors: HashMap<Index, Player>,
     ) {
         assert!(times.is_empty() || self.time, "length(times)>0 but !h.time");
         assert!(
@@ -267,6 +267,8 @@ impl History {
             "(length(weights) > 0) & (length(composition) != length(weights))"
         );
 
+        agent::clean(self.agents.values_mut(), true);
+
         let mut unique = Vec::with_capacity(100);
 
         let this_agent = composition
@@ -289,7 +291,7 @@ impl History {
                 self.agents.insert(
                     **agent,
                     Agent {
-                        player: priors.get(agent).cloned().unwrap_or_else(|| {
+                        player: priors.remove(agent).unwrap_or_else(|| {
                             Player::new(
                                 Gaussian::from_ms(self.mu, self.sigma),
                                 self.beta,
@@ -302,8 +304,6 @@ impl History {
             }
         }
 
-        agent::clean(self.agents.values_mut(), true);
-
         let n = composition.len();
         let o = if self.time {
             sort_time(&times, false)
@@ -331,6 +331,7 @@ impl History {
                     batch.new_forward_info(&self.agents);
                 }
 
+                // TODO: Is it faster to iterate over agents in batch instead?
                 for agent_idx in &this_agent {
                     if let Some(skill) = batch.skills.get_mut(agent_idx) {
                         skill.elapsed =
@@ -398,6 +399,7 @@ impl History {
 
             batch.new_forward_info(&self.agents);
 
+            // TODO: Is it faster to iterate over agents in batch instead?
             for agent_idx in &this_agent {
                 if let Some(skill) = batch.skills.get_mut(agent_idx) {
                     skill.elapsed =