diff --git a/src/board/chess_board/error.rs b/src/board/chess_board/error.rs
index 5af3b25..b1ed769 100644
--- a/src/board/chess_board/error.rs
+++ b/src/board/chess_board/error.rs
@@ -30,24 +30,24 @@ pub enum ValidationError {
 impl std::fmt::Display for ValidationError {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
         let error_msg = match self {
-            Self::TooManyPieces => "Too many pieces",
-            Self::MissingKing => "Missing king",
-            Self::InvalidPawnPosition => "Pawns on the first/last rank",
+            Self::TooManyPieces => "too many pieces",
+            Self::MissingKing => "missing king",
+            Self::InvalidPawnPosition => "pawns on the first/last rank",
             Self::InvalidCastlingRights => {
-                "Castling rights do not match up with the state of the board"
+                "castling rights do not match up with the state of the board"
             }
             Self::InvalidEnPassant => {
-                "En-passant target square is not empty, behind an opponent's pawn, on the correct rank"
+                "en-passant target square is not empty, behind an opponent's pawn, on the correct rank"
             }
-            Self::NeighbouringKings => "The two kings are next to each other",
-            Self::OpponentInCheck => "The opponent is currently in check",
-            Self::OverlappingPieces => "The piece-specific boards are overlapping",
-            Self::OverlappingColors => "The color-specific boards are overlapping",
+            Self::NeighbouringKings => "the two kings are next to each other",
+            Self::OpponentInCheck => "the opponent is currently in check",
+            Self::OverlappingPieces => "the piece-specific boards are overlapping",
+            Self::OverlappingColors => "the color-specific boards are overlapping",
             Self::ErroneousCombinedOccupancy => {
-                "The pre-computed combined occupancy boards does not match the other boards"
+                "the pre-computed combined occupancy boards does not match the other boards"
             }
-            Self::HalfMoveClockTooHigh => "Half-move clock is higher than total number of plies",
-            Self::IncoherentPlieCount => "The total plie count does not match the current player",
+            Self::HalfMoveClockTooHigh => "half-move clock is higher than total number of plies",
+            Self::IncoherentPlieCount => "the total plie count does not match the current player",
         };
         write!(f, "{}", error_msg)
     }
diff --git a/src/fen.rs b/src/fen.rs
index df4005d..4c05879 100644
--- a/src/fen.rs
+++ b/src/fen.rs
@@ -21,8 +21,8 @@ pub enum FenError {
 impl std::fmt::Display for FenError {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
         match self {
-            Self::InvalidFen => write!(f, "Invalid FEN input"),
-            Self::InvalidPosition(err) => write!(f, "Invalid chess position: {}", err),
+            Self::InvalidFen => write!(f, "invalid FEN input"),
+            Self::InvalidPosition(err) => write!(f, "invalid chess position: {}", err),
         }
     }
 }